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  • Engineering  (6,322)
  • Inorganic Chemistry  (5,395)
  • GEOPHYSICS
  • 2015-2019  (45)
  • 1995-1999  (4,957)
  • 1990-1994  (10,227)
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  • 1
    Publication Date: 2021-05-19
    Description: Aleksey Sergeevich Vinnov (25.05.1958 – 04.06.2019) was a Candidate of Sciences (Engineering), an Associate Professor, a talented lecturer, a rector of the Kerch Maritime Technological Institute (KMTI) in 2000–2005, a Senior Researcher in the FSBSI “Southern Scientific Research Institute of Marine Fisheries and Oceanography” (YugNIRO), and a Deputy Head for Operation and Quality of the Limited Liability Company under the Laws of Russian Federation “Aquamarine”. A.S. Vinnov made a great contribution into the development of education and science in the field of fisheries. Aleksey Sergeevich began his professional life as a Junior Researcher in the Astrakhan Technical Institute of Fishing Industry and Economy and defended his Candidate's Thesis in 1988. He dedicated the major part of his working career to the Kerch State Maritime Technological University, where he had been employed for 21 years, taking positions from a senior lecturer of the Department of Fish Processing Technology, an Associate Professor, the Dean of the Technological Faculty, the vice-rector for academic affairs, to the rector of the University. A.S. Vinnov was known for his rational thinking and professional integrity; he was diplomatic and considerate, and proved to be a competent leader. Vinnov's research works were dedicated to the issues of development of production technology for canned fish and fish protein mass, of kinetics of enzymatic hydrolysis, and many other subjects. A.S. Vinnov was honored with several badges of distinction due to his high professional expertise and personal contribution to the development of fisheries field, particularly education.
    Description: Алексей Сергеевич Виннов (25.05.1958 – 04.06.2019 гг.) — кандидат технических наук, доцент, талантливый преподаватель, ректор Керченского морского технологического института с 2000 по 2005 г. (КМТИ), старший научный сотрудник ФГБНУ «Южный научно-исследовательский институт рыбного хозяйства и океанографии» (ЮгНИРО), заместитель директора по производству и качеству ООО «Аквамарин». А.С. Виннов внес огромный вклад в развитие образования и науки рыбной отрасли. Свою трудовую деятельность Алексей Сергеевич начал в должности младшего научного сотрудника Астраханского технического института рыбной промышленности и хозяйства, успешно защитив в 1988 г. кандидатскую диссертацию. Большую часть своей трудовой деятельности он посвятил Керченскому государственному морскому технологическому университету, проработав здесь 21 год в должностях от старшего преподавателя кафедры технологии рыбных продуктов, доцента, декана технологического факультета, проректора по учебной работе до ректора университета. А.С. Виннов обладал рациональным мышлением, был очень грамотным, тактичным человеком, умелым руководителем. Научная деятельность Алексея Сергеевича была посвящена изучению вопросов усовершенствования технологии рыбных консервов, рыбных белковых масс, кинетики ферментативного гидролиза, а также многим другим. За личный вклад в развитие образования и рыбной отрасли, за высокий профессионализм А.С. Виннов был удостоен ряда почетных знаков отличия.
    Description: Published
    Keywords: Researchers ; Engineering ; Fish processing ; Canned food ; Rector ; Proteins ; Hydrolysis
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.91-95
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  • 2
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2018-08-17
    Keywords: Engineering
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2018-08-17
    Description: Polyamide thickness and roughness have been identified as critical properties that affect thin-film composite membrane performance for reverse osmosis. Conventional formation methodologies lack the ability to control these properties independently with high resolution or precision. An additive approach is presented that uses electrospraying to deposit monomers directly onto a substrate, where they react to form polyamide. The small droplet size coupled with low monomer concentrations result in polyamide films that are smoother and thinner than conventional polyamides, while the additive nature of the approach allows for control of thickness and roughness. Polyamide films are formed with a thickness that is controllable down to 4-nanometer increments and a roughness as low as 2 nanometers while still exhibiting good permselectivity relative to a commercial benchmarking membrane.
    Keywords: Engineering
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    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2018-09-07
    Description: Zeolitic imidazolate framework (ZIF) membranes are emerging as a promising energy-efficient separation technology. However, their reliable and scalable manufacturing remains a challenge. We demonstrate the fabrication of ZIF nanocomposite membranes by means of an all-vapor-phase processing method based on atomic layer deposition (ALD) of ZnO in a porous support followed by ligand-vapor treatment. After ALD, the obtained nanocomposite exhibits low flux and is not selective, whereas after ligand-vapor (2-methylimidazole) treatment, it is partially transformed to ZIF and shows stable performance with high mixture separation factor for propylene over propane (an energy-intensive high-volume separation) and high propylene flux. Membrane synthesis through ligand-induced permselectivation of a nonselective and impermeable deposit is shown to be simple and highly reproducible and holds promise for scalability.
    Keywords: Engineering
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    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 5
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2018-09-14
    Keywords: Engineering
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 6
    Publication Date: 2018-09-14
    Description: Insects are among the most agile natural flyers. Hypotheses on their flight control cannot always be validated by experiments with animals or tethered robots. To this end, we developed a programmable and agile autonomous free-flying robot controlled through bio-inspired motion changes of its flapping wings. Despite being 55 times the size of a fruit fly, the robot can accurately mimic the rapid escape maneuvers of flies, including a correcting yaw rotation toward the escape heading. Because the robot’s yaw control was turned off, we showed that these yaw rotations result from passive, translation-induced aerodynamic coupling between the yaw torque and the roll and pitch torques produced throughout the maneuver. The robot enables new methods for studying animal flight, and its flight characteristics allow for real-world flight missions.
    Keywords: Engineering
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    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 7
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2018-04-27
    Keywords: Engineering
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2018-09-14
    Keywords: Engineering
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 9
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2018-03-09
    Keywords: Engineering
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 10
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2018-01-19
    Keywords: Engineering
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 11
    Unknown
    Berlin, Heidelberg : Springer Vieweg
    Keywords: Engineering ; Robotics ; Automation ; Industrial engineering ; Production engineering ; Economic sociology ; Engineering ; Industrial and Production Engineering ; Organizational Studies, Economic Sociology ; Robotics and Automation
    Description / Table of Contents: Einleitung --- Prognostizierte Veränderungen der gestaltbaren Arbeitssystemdimensionen --- Systeme zur Assistenz und Effizienzsteigerung in manuellen Produktionsprozessen der Industrie auf Basis von Projektion und Tiefendatenerkennung --- Betriebliche Auswirkungen industrieller Servicerobotik am Beispiel der Kleinteilemontage --- Erweiterte Horizonte – Ein technischer Blick in die Zukunft der Arbeit --- Soziotechnische Assistenzsysteme für die Produktionsarbeit in der Textilbranche --- Lernförderliche Arbeitssysteme für die Arbeitswelt von morgen --- Assistenz und Wissensvermittlung am Beispiel von Montage- und Instandhaltungstätigkeiten --- Der Mensch in Interaktion mit autonomen Planungs- und Steuerungssystemen für Cyber-Physische Produktionssysteme --- ReApp – Wiederverwendbare Roboterapplikationen für flexible Roboteranlagen - Auswirkungen der Ergebnisse aus ReApp auf betriebliche Funktionen am Beispiel eines Anwendungsfalls in der Elektroindustrie --- Modellierungsansatz für ein arbeitsplatznahes Beschreibungsmodell der »Arbeitswelt Industrie 4.0 --- Die Zukunft der Arbeit im demografischen Wandel --- “Social Manufacturing and Logistics“ – Arbeit in der digitalisierten Produktion --- Lernförderliche Arbeitsorganisation in der Industrie 4.0 --- Decision Support Pipelines – Durchgängige Datenverarbeitungsinfrastrukturen für die Entscheidungen von morgen --- Gerechtigkeit in flexiblen Arbeits- und Managementprozessen --- Technologie, Organisation, Qualifikation
    Pages: Online-Ressource (XI, 246 Seiten) , 62 Abbildungen, 56 Abbildungen in Farbe
    ISBN: 9783662492666
    Language: German
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  • 12
    Publication Date: 2021-05-19
    Description: Наряду с исследованиями по определению сырьевой базы Азово-Черноморского бассейна, при создании института АзЧерНИРО в 1933 г. была сразу организована научно-исследовательская лаборатория техники лова рыбы. За все время функционирования этого подразделения такие специалисты, как С.С. Виннов, О.И. Саковец, С.Я. Наместников, Е.Е. Шапунов, В.М. Кириллов, В.Г. Герасимов, В.С. Долбиш, Н.Г. Думин, В.Г. Васильев, А.А. Яковлев, Е.С. Деньгин, В.И. Абакаров, В.Н. Миронов, В.В. Стрельцов, А.С. Вайнерман, В.К. Яшкин, Ю.В. Шишов, А.М. Стафикопуло в течение многих лет вносили огромный вклад в развитие рыболовства в Азово-Черноморском бассейне и Мировом океане. До 1950 г. траловый промысел в Черном море отсутствовал, хотя были известны попытки внедрить этот вид лова в черноморское рыболовство. Так, в начале 1909 г. в северо-западной части Черного моря работал траулер «Федя». К концу 1911 г. количество траулеров, которые работали в данном регионе моря, увеличилось до 9 судов. Уловы состояли на 98-99 % из осетровых и на 1-2 % из камбалы. Ввиду очень большого вылова молоди осетровых рыб траловый промысел вскоре был запрещен. В 1932 г. из Мурманска для выяснения эффективности тралового лова в Черном море был послан рыболовный траулер «Абрек». Почти у всего черноморского побережья пробовали ловить отечественным промысловым тралом, применяемым в Баренцевом море для добычи трески. При этом отмечалось, что уловы камбалы были очень низкими. Очевидно, одной из причин была неприспособленность самой конструкции трала для лова этого вида рыб. В конце 1933 г. траулер вернулся в Мурманск. В 1949 г. Черноморская научно-промысловая экспедиция возобновила работы по освоению тралового лова в Черном море. Перед экспедицией стояла задача всесторонне изучить ихтиофауну моря и выяснить возможности применения ряда поисковых орудий лова, в том числе донного трала. С этой целью было разработано и испытано несколько типов донных тралов. С конца 1949 г. были начаты исследования по разработке конструкции разноглубинного трала для Черного моря. К тому времени инженерами М.К. Кокоревым, В.Ф. Шушпановым и А.Н. Потехиным была разработана специальная подъемно-распорная система. В соответствии с ее техническими данными в дальнейшем проектировались сетные части трала. Первый проект опытного рыболовного разноглубинного морского трала разрабатывался для лова мелких черноморских пелагических рыб в толще воды, на глубинах от 0 до 100 м, с одного судна. Большой вклад в развитие тралового промысла в Черном море внес А.Н. Самарянов.
    Description: Published
    Keywords: Engineering ; Fishing gear ; Fishing fleet ; Fishing vessels ; Trawlers ; Anchovy fisheries ; Sprat fisheries ; Purse fishing ; Commercial species ; Mullets
    Repository Name: AquaDocs
    Type: Conference Material , Non Refereed
    Format: pp.247-254
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  • 13
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-06-23
    Keywords: Engineering
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 14
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-06-23
    Keywords: Engineering
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    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 15
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-06-16
    Keywords: Engineering
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  • 16
    Publication Date: 2017-06-23
    Description: Exoskeletons and active prostheses promise to enhance human mobility, but few have succeeded. Optimizing device characteristics on the basis of measured human performance could lead to improved designs. We have developed a method for identifying the exoskeleton assistance that minimizes human energy cost during walking. Optimized torque patterns from an exoskeleton worn on one ankle reduced metabolic energy consumption by 24.2 ± 7.4% compared to no torque. The approach was effective with exoskeletons worn on one or both ankles, during a variety of walking conditions, during running, and when optimizing muscle activity. Finding a good generic assistance pattern, customizing it to individual needs, and helping users learn to take advantage of the device all contributed to improved economy. Optimization methods with these features can substantially improve performance.
    Keywords: Engineering
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  • 17
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-11-24
    Keywords: Engineering
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    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 18
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-12-01
    Description: Kim et al . (Reports, 28 April 2017, p. 430) presented results for the solar-driven harvesting of water from air via metal-organic frameworks as a prodigious potential advance toward remedying global water shortages. Basic thermodynamics and a survey of multiple off-the-shelf technologies show that their approach is vastly inferior in efficiency (and thereby in feasibility) to available alternatives.
    Keywords: Engineering
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  • 19
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-12-01
    Keywords: Engineering
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    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 20
    Publication Date: 2017-12-01
    Description: In their comment, Bui et al . argue that the approach we described in our report is vastly inferior in efficiency to alternative off-the-shelf technologies. Their conclusion is invalid, as they compare efficiencies in completely different operating conditions. Here, using heat transfer and thermodynamics principles, we show how Bui et al .’s conclusions about the efficiencies of off-the-shelf technologies are fundamentally flawed and inaccurate for the operating conditions described in our study.
    Keywords: Engineering
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  • 21
    Publication Date: 2017-05-12
    Description: Bacteria within communities can interact to organize their behavior. It has been unclear whether such interactions can extend beyond a single community to coordinate the behavior of distant populations. We discovered that two Bacillus subtilis biofilm communities undergoing metabolic oscillations can become coupled through electrical signaling and synchronize their growth dynamics. Coupling increases competition by also synchronizing demand for limited nutrients. As predicted by mathematical modeling, we confirm that biofilms resolve this conflict by switching from in-phase to antiphase oscillations. This results in time-sharing behavior, where each community takes turns consuming nutrients. Time-sharing enables biofilms to counterintuitively increase growth under reduced nutrient supply. Distant biofilms can thus coordinate their behavior to resolve nutrient competition through time-sharing, a strategy used in engineered systems to allocate limited resources.
    Keywords: Engineering
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  • 22
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-05-12
    Keywords: Engineering
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    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 23
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-02-10
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
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  • 24
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-01-27
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
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    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 25
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-02-17
    Description: Engineering has an image problem. The phrase "engineering disaster" rolls off the tongue, while great technical achievements are more often heralded as "scientific miracles." Enter Dream Big. Sponsored by the American Society of Civil Engineers with support from Bechtel Corporation, the film sets out to reframe engineering as a force for good and a profession in service to people and the planet. Author: Donna Riley
    Keywords: Engineering
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  • 26
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-07-21
    Keywords: Engineering
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    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 27
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-07-21
    Keywords: Engineering
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    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 28
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-05-26
    Keywords: Engineering
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    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 29
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-11-10
    Keywords: Engineering
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    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 30
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2017-01-27
    Description: Polynitrogens have the potential for ultrahigh-performing explosives or propellants because singly or doubly bonded polynitrogens can decompose to triply bonded dinitrogen (N2) with an extraordinarily large energy release. The large energy content and relatively low activation energy toward decomposition makes the synthesis of a stable polynitrogen allotrope an extraordinary challenge. Many elements exist in different forms (allotropes)—for example, carbon can exist as graphite, diamond, buckyballs, or graphene. However, no stable neutral allotropes are known for nitrogen, and only two stable homonuclear polynitrogen ions had been isolated until now—namely, the N3− anion (1) and the N5+ cation (2). On page 374 of this issue, Zhang et al. (3) report the synthesis and characterization of the first stable salt of the cyclo-N5− anion, only the third stable homonuclear polynitrogen ion ever isolated. Author: Karl O. Christe
    Keywords: Inorganic Chemistry
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  • 31
    Keywords: Engineering ; Project management ; Engineering design ; Automotive Engineering ; Project Management ; Engineering Design
    Description / Table of Contents: A - Die Entwicklung: Drei Erfolgsstories --- Die StreetScooter-Gründer-Story --- Die StreetScooter-Meilensteine 2008-2017 --- Die StreetScooter-Entwicklungsstory --- Die StreetScooter-Protagonisten-Story --- B - Die Lösung: Return on Engineering: Die StreetScooter-Lösungsbausteine. C - Die Perspektive: Die StreetScooter-Netzwerk-Story --- Die StreetScooter-Produktions-Story --- Die StreetScooter-Post-Story --- Die StreetScooter-Mobilitätslösung --- Die StreetScooter-Vision. A - The Development: Three Stories of Success --- The StreetScooter Founder Story --- The StreetScooter Milestones 2008-2017 --- The StreetScooter Development Story --- The StreetScooter Protagonists Story --- B - The Solution: Return on Engineering: The StreetScooter Building Blocks --- C - The Perspective: The StreetScooter Network Story --- The StreetScooter Production Story --- The StreetScooter Post Story --- The StreetScooter Mobility Solution --- The StreetScooter Vision
    Pages: Online-Ressource (VII, 213 Seiten)
    ISBN: 9783662549971
    Language: German
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  • 32
    Keywords: Earth sciences ; Natural disasters ; Engineering geology ; Engineering ; Geology ; Foundations ; Hydraulics ; Sustainable development ; Earth Sciences ; Natural Hazards ; Geoengineering, Foundations, Hydraulics ; Sustainable Development
    Description / Table of Contents: ISDR-ICL Sendai Partnerships 2015-2025 --- The ISDR-ICL Sendai Partnerships 2015-2025: Background and Content --- Forum lectures --- Rupestrian world heritage sites: Instability investigation and sustainable mitigation --- Subaerial landslide-generated waves: Numerical and laboratory simulations --- Rockfall occurrence and fragmentation --- Contribution from signatory organizations of the Sendai Partnerships --- International Consortium on Landslides (ICL) --- International Consortium on Landslides (ICL) - The proposing organization of the ISDR-ICL Sendai partnerships 2015-2025 --- United Nations Office for Disaster Risk Reduction (UNISDR) --- UNISDR‘s Contribution to Science and Technology for Disaster Risk Reduction and the Role of the International Consortium on Landslides (ICL) --- United Nations Educational, Scientific and Cultural Organization (UNESCO) --- UNESCO’s Contribution to the Implementation of UNISDR’s Global Initiative and ICL --- United Nations University (UNU) --- The United Nations University: Research and Policy Support for Environmental Risk Reduction --- World Meteorological Organization (WMO) --- Concerted International Efforts for Advancing Multi-Hazard Early Warning Systems --- International Council for Science (ICSU) --- On Future Challenges for the Integration of Science into International Policy Development for Landslide Disaster Risk Reduction --- World Federation of Engineering Organizations (WFEO) --- World Federation of Engineering Organizations Activities in Disaster Risk Reduction --- Disaster Prevention Research Institute (DPRI), Kyoto University --- National Civil Protection Department, Italian Presidency of the Council of Ministers, Government of Italy --- Understanding and Reducing Landslide Disaster Risk: Challenges and Opportunities for Italian Civil Protection --- Landslide Dynamics: ISDR-ICL Landslide Interactive Teaching Tools (LITT) --- Progress of the World Report on Landslides --- International Programme on Landslides (IPL): Objectives, History and List of World Centres of Excellence and IPL Projects --- UNESCO-KU-ICL UNITWIN Cooperation Programme for Landslides and Water-Related Disaster Risk Management. Landslides: Journal of the International Consortium on Landslides --- IPL Activities --- Advanced Technologies for Landslides (WCoE 2014-2017, IPL-196, IPL-198) --- Mechanisms of Landslides and Creep in Over-Consolidated Clays and Flysch (WCoE 2014-2017 --- Research on Heavy-Rainfall-Induced and Hydraulic-Driven Geological Hazards in China (WCoE 2014-2017). Landslide Risk Reduction in Croatia: Scientific research in the framework of the WCoE 2014-2017, IPL-173, IPL-184, ICL ABN --- Shapes and Mechanisms of Large-scale Landslides in Japan: Forecasting Analysis from an Inventory (WCoE 2014–2017 --- Retrospective and Prospects for Cold Regions Landslide Research (2012-2016) (WCoE 2014-2017, IPL-132, IPL-167, IPL-203, CRLN --- Large-scale Rockslide Inventories: from the Kokomeren River Basin to the Entire Central Asia Region (WCoE 2014-2017, IPL-106-2) --- Interventions for Promoting Knowledge, Innovations and Landslide Risk Management Practices within South and Southeast Asia (WCoE 2014-2017) --- Promoting a Global Standard for Community-based Landslide Early Warning Systems (WCoE 2014-2017, IPL-158, IPL-165) --- Model Policy Frameworks, Standards and Guidelines on Landslide Disaster Reduction (WCoE 2014-2017) --- Landslide Hazard and Risk Management (WCoE 2014-2017) --- Mitigation of Landslide Hazards in Ukraine under the Guidance of ICL: 2009–2016 (IPL-153, IPL-191) --- Development of a Hazard Evaluation Technique for Earthquake-Induced Landslides Based on an Analytic Hierarchy Process (AHP) (IPL-154) --- The Croatian-Japanese SATREPS Joint Research Project on Landslides (IPL-161)
    Pages: Online-Ressource (XXVI, 586 pages) , 372 illustrations, 350 illustrations in color
    ISBN: 9783319594699
    Language: English
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  • 33
    Keywords: Earth sciences ; Natural disasters ; Engineering geology ; Engineering ; Geology ; Foundations ; Hydraulics ; Sustainable development ; Earth Sciences ; Natural Hazards ; Geoengineering, Foundations, Hydraulics ; Sustainable Development
    Description / Table of Contents: ISDR-ICL Sendai Partnerships 2015-2025 --- The ISDR-ICL Sendai Partnerships 2015-2025: Background and Content --- Forum lectures --- Rupestrian world heritage sites: Instability investigation and sustainable mitigation --- Subaerial landslide-generated waves: Numerical and laboratory simulations --- Rockfall occurrence and fragmentation --- Contribution from signatory organizations of the Sendai Partnerships --- International Consortium on Landslides (ICL) --- International Consortium on Landslides (ICL) - The proposing organization of the ISDR-ICL Sendai partnerships 2015-2025 --- United Nations Office for Disaster Risk Reduction (UNISDR) --- UNISDR‘s Contribution to Science and Technology for Disaster Risk Reduction and the Role of the International Consortium on Landslides (ICL) --- United Nations Educational, Scientific and Cultural Organization (UNESCO) --- UNESCO’s Contribution to the Implementation of UNISDR’s Global Initiative and ICL --- United Nations University (UNU) --- The United Nations University: Research and Policy Support for Environmental Risk Reduction --- World Meteorological Organization (WMO) --- Concerted International Efforts for Advancing Multi-Hazard Early Warning Systems --- International Council for Science (ICSU) --- On Future Challenges for the Integration of Science into International Policy Development for Landslide Disaster Risk Reduction --- World Federation of Engineering Organizations (WFEO) --- World Federation of Engineering Organizations Activities in Disaster Risk Reduction --- Disaster Prevention Research Institute (DPRI), Kyoto University --- National Civil Protection Department, Italian Presidency of the Council of Ministers, Government of Italy --- Understanding and Reducing Landslide Disaster Risk: Challenges and Opportunities for Italian Civil Protection --- Landslide Dynamics: ISDR-ICL Landslide Interactive Teaching Tools (LITT) --- Progress of the World Report on Landslides --- International Programme on Landslides (IPL): Objectives, History and List of World Centres of Excellence and IPL Projects --- UNESCO-KU-ICL UNITWIN Cooperation Programme for Landslides and Water-Related Disaster Risk Management. Landslides: Journal of the International Consortium on Landslides --- IPL Activities --- Advanced Technologies for Landslides (WCoE 2014-2017, IPL-196, IPL-198) --- Mechanisms of Landslides and Creep in Over-Consolidated Clays and Flysch (WCoE 2014-2017 --- Research on Heavy-Rainfall-Induced and Hydraulic-Driven Geological Hazards in China (WCoE 2014-2017). Landslide Risk Reduction in Croatia: Scientific research in the framework of the WCoE 2014-2017, IPL-173, IPL-184, ICL ABN --- Shapes and Mechanisms of Large-scale Landslides in Japan: Forecasting Analysis from an Inventory (WCoE 2014–2017 --- Retrospective and Prospects for Cold Regions Landslide Research (2012-2016) (WCoE 2014-2017, IPL-132, IPL-167, IPL-203, CRLN --- Large-scale Rockslide Inventories: from the Kokomeren River Basin to the Entire Central Asia Region (WCoE 2014-2017, IPL-106-2) --- Interventions for Promoting Knowledge, Innovations and Landslide Risk Management Practices within South and Southeast Asia (WCoE 2014-2017) --- Promoting a Global Standard for Community-based Landslide Early Warning Systems (WCoE 2014-2017, IPL-158, IPL-165) --- Model Policy Frameworks, Standards and Guidelines on Landslide Disaster Reduction (WCoE 2014-2017) --- Landslide Hazard and Risk Management (WCoE 2014-2017) --- Mitigation of Landslide Hazards in Ukraine under the Guidance of ICL: 2009–2016 (IPL-153, IPL-191) --- Development of a Hazard Evaluation Technique for Earthquake-Induced Landslides Based on an Analytic Hierarchy Process (AHP) (IPL-154) --- The Croatian-Japanese SATREPS Joint Research Project on Landslides (IPL-161)
    Pages: Online-Ressource (XXVI, 586 pages) , 372 illustrations, 350 illustrations in color
    ISBN: 9783319594699
    Language: English
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  • 34
    Unknown
    Berlin, Heidelberg : Springer Vieweg
    Keywords: Engineering ; Humanities ; Digital libraries ; Computers ; Educational technology ; Electrical engineering ; Engineering ; Communications Engineering, Networks ; Information Systems and Communication Service ; Digital Humanities ; Technology and Digital Education
    Description / Table of Contents: Seit Jahren wird unser Alltag geprägt von zunehmender Automation und Vernetzung, die Digitalisierung genannt wird. Sensoren erfassen immer mehr unterschiedliche Daten und werden von intelligenten Algorithmen zunehmend präzisier analysiert. Dies führt nicht nur zu einem anderen Verhältnis im Umgang und bei der Nutzung von Daten durch Menschen und Maschinen, sondern wird auch dramatisch Aufgaben und Prozesse verändern. Die damit verbundenen Arbeitsanforderungen werden zum massiven Wandel von Berufsbildern führen, in dem einfache Tätigkeiten automatisiert und komplexe Tätigkeiten vereinfacht werden. Nicht nur das Arbeiten sondern auch das Lernen, Lehren und Forschen verändert sich durch die Digitalisierung. Die technischen Möglichkeiten wandeln die Lebenswelten mit ihren urbanen Versorgungs- und Infrastrukturen und eröffnen den Wirtschaftsräumen neue Geschäftsmodelle. Diese parallel einsetzenden Entwicklungen führen zu radikalen Umbrüchen, die in den kommenden Jahren sämtliche Aspekte der Gesellschaft verändern werden
    Pages: Online-Ressource (IX, 199 Seiten)
    ISBN: 9783662528549
    Language: German
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  • 35
    Unknown
    Berlin, Heidelberg : Springer Vieweg
    Keywords: Engineering ; Humanities ; Digital libraries ; Computers ; Educational technology ; Electrical engineering ; Engineering ; Communications Engineering, Networks ; Information Systems and Communication Service ; Digital Humanities ; Technology and Digital Education
    Description / Table of Contents: Seit Jahren wird unser Alltag geprägt von zunehmender Automation und Vernetzung, die Digitalisierung genannt wird. Sensoren erfassen immer mehr unterschiedliche Daten und werden von intelligenten Algorithmen zunehmend präzisier analysiert. Dies führt nicht nur zu einem anderen Verhältnis im Umgang und bei der Nutzung von Daten durch Menschen und Maschinen, sondern wird auch dramatisch Aufgaben und Prozesse verändern. Die damit verbundenen Arbeitsanforderungen werden zum massiven Wandel von Berufsbildern führen, in dem einfache Tätigkeiten automatisiert und komplexe Tätigkeiten vereinfacht werden. Nicht nur das Arbeiten sondern auch das Lernen, Lehren und Forschen verändert sich durch die Digitalisierung. Die technischen Möglichkeiten wandeln die Lebenswelten mit ihren urbanen Versorgungs- und Infrastrukturen und eröffnen den Wirtschaftsräumen neue Geschäftsmodelle. Diese parallel einsetzenden Entwicklungen führen zu radikalen Umbrüchen, die in den kommenden Jahren sämtliche Aspekte der Gesellschaft verändern werden
    Pages: Online-Ressource (IX, 199 Seiten)
    ISBN: 9783662528549
    Language: German
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  • 36
    Unknown
    Berlin, Heidelberg : Springer Vieweg
    Keywords: Engineering ; Humanities ; Digital libraries ; Educational technology ; Electrical engineering ; Engineering ; Communications Engineering, Networks ; Digital Humanities ; Technology and Digital Education
    Description / Table of Contents: Vorwort --- Einleitung --- Bürger --- Wenn Bots sich unter Leute mischen: Social Bots in den Sozialen Medien --- Digitale Partizipation in Wissenschaft und Wirtschaft --- Entwicklung einer soziodigitalen Souveränität --- Unternehmen --- Digitale Souveränität – ein mehrdimensionales Handlungskonzept für die deutsche Wirtschaft --- Privatheit und digitale Souveränität in der Arbeitswelt 4.0 --- Staat --- Mehr Daten, weniger Vertrauen in Statistik – freie Fahrt für ‚alternative Fakten‘? --- Internationale Perspektiven auf digitale Souveränität --- Digitalisierung der Bildung als staatliche Aufgabe --- Ausblick
    Pages: Online-Ressource (IX, 187 Seiten) , 40 Abbildungen in Farbe
    ISBN: 9783662557969
    Language: German
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  • 37
    Unknown
    Berlin, Heidelberg : Springer Vieweg
    Keywords: Engineering ; Humanities ; Digital libraries ; Educational technology ; Electrical engineering ; Engineering ; Communications Engineering, Networks ; Digital Humanities ; Technology and Digital Education
    Description / Table of Contents: Vorwort --- Einleitung --- Bürger --- Wenn Bots sich unter Leute mischen: Social Bots in den Sozialen Medien --- Digitale Partizipation in Wissenschaft und Wirtschaft --- Entwicklung einer soziodigitalen Souveränität --- Unternehmen --- Digitale Souveränität – ein mehrdimensionales Handlungskonzept für die deutsche Wirtschaft --- Privatheit und digitale Souveränität in der Arbeitswelt 4.0 --- Staat --- Mehr Daten, weniger Vertrauen in Statistik – freie Fahrt für ‚alternative Fakten‘? --- Internationale Perspektiven auf digitale Souveränität --- Digitalisierung der Bildung als staatliche Aufgabe --- Ausblick
    Pages: Online-Ressource (IX, 187 Seiten) , 40 Abbildungen in Farbe
    ISBN: 9783662557969
    Language: German
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  • 38
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2016-07-08
    Description: The Internet connects billions of computational platforms of various sizes, from supercomputers to smart phones. However, the same types of data transmission can connect computational resources to much simpler sensors “at the edge of the net” that collect, analyze, and transmit data, as well as controllers that receive instructions. Devices deployed in the environment, homes and offices, and even our bodies would expand the number of connected devices to the trillions. This “Internet of Things” (IoT) underlies the vision of smart homes and buildings that could sense and transmit their status and respond appropriately (1), or track and report on the state of objects (vehicles, goods, or even animals) in the environment. However, the practical implementation of the IoT has been relatively slow, in part because all of these edge devices must draw electrical power from their local environment. We analyze the use of photovoltaics (PV) to power devices and help bring the IoT to fruition. Authors: Richard Haight, Wilfried Haensch, Daniel Friedman
    Keywords: Engineering
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 39
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2016-04-22
    Description: So prized by the ancient Romans were Egyptian obelisks that, at one time, more of them stood in Rome than in Egypt. In the 19th century, France, Britain, and the United States—inspired by Napoleon Bonaparte's expedition to Egypt in 1798— acquired their own major obelisks from Alexandria and Luxor. Cleopatra's Needles, by Egyptologist Bob Brier, explores the engineering challenges associated with building and erecting these massive monuments. Author: Andrew Robinson
    Keywords: Engineering
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 40
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2016-10-21
    Description: A physicist reveals the engineering marvels that underlie the modern metropolis Author: Sybil Derrible
    Keywords: Engineering
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 41
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2016-09-09
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 42
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2016-11-11
    Description: Author: Jake Yeston
    Keywords: Inorganic Chemistry
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 43
    Keywords: Engineering ; Commercial law ; Automotive engineering ; Robotics ; Automation ; Community psychology ; Environmental psychology ; Engineering ; Automotive Engineering ; Robotics and Automation ; Community and Environmental Psychology ; Commercial Law
    Description / Table of Contents: Teil I Human and Machine --- Teil II Mobilität --- Teil III Verkehr --- Teil IV Sicherheit --- Teil V Recht und Haftung --- Teil VI Akzeptanz
    Pages: Online-Ressource (XIV, 732 Seiten)
    ISBN: 9783662458549
    Language: German
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  • 44
    Unknown
    Berlin, Heidelberg : Springer Vieweg
    Keywords: Engineering ; Robotics ; Automation ; Industrial engineering ; Production engineering ; Engineering economics ; Engineering economy ; Manufacturing industries ; Machines ; Tools ; Engineering ; Industrial and Production Engineering ; Robotics and Automation ; Engineering Economics, Organization, Logistics, Marketing ; Manufacturing, Machines, Tools ; Information Systems Applications (incl. Internet)
    Description / Table of Contents: Einordnung und Hintergründe --- Positionen der Sozialpartner --- Erfahrungen und Herausforderungen in der Industrie --- Forschungsfragen und Entwicklungsstrategien --- Ausblick
    Pages: Online-Ressource (VIII, 167 Seiten) , 38 Abbildungen
    ISBN: 9783662459157
    Language: German
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  • 45
    Keywords: Engineering ; Computer simulation ; Economic theory ; Data-driven Science, Modeling and Theory Building ; Complexity ; Simulation and Modeling ; Applications of Graph Theory and Complex Networks ; Economic Theory/Quantitative Economics/Mathematical Methods
    Description / Table of Contents: Chapter 1 Financial Market --- Influence Networks in the Foreign Exchange Market --- Entropy and Transfer Entropy: The Dow Jones and the build up to the 1997 Asian Crisis --- Execution and Cancellation Lifetimes in Foreign Currency Market --- Signs of market orders and human dynamics --- Damped oscillatory behaviors in the ratios of stock market indices --- Exploring Market Making Strategy for High Frequency Trading: an Agent-based Approach --- Effect of Cancel Order on Simple Stochastic Order-Book Model --- Chapter 2 Robustness and Fragility --- Cascading failures in interdependent economic networks --- Do connections make systems robust?: a new scenario for the complexity-stability relation --- Simulation of Gross Domestic Product in International Trade Networks: Linear Gravity Transportation Model --- Analysis of Network Robustness for a Japanese Business Relation Network by Percolation Simulation.- Detectability threshold of the spectral method for graph partitioning.- Spread of Infectious Diseases with a Latent Period.-Chapter 3 Interaction and Distribution --- Geographic Dependency of Population Distribution- Spatiotemporal Analysis of Influenza Epidemics in Japan --- A Universal Lifetime Distribution for Multi-Species Systems --- Firm Age Distributions and the Decay Rate of Firm Activities --- Empirical Analysis of Firm-Dynamics on Japanese Inter-firm trade Network --- Direct participants’ behavior through the lens of transactional analysis: the case of SPEI --- Chapter 4 Traffic and Pedestrian --- Pedestrian Dynamics in Jamology --- Qualitative Methods of Validating Evacuation Behaviors --- Collective dynamics of pedestrians with no fixed destination --- Traffic Simulation of Kobe-city --- MOSAIIC: city-level agent-based traffic simulation adapted to emergency situations --- GUI for Agent Based Modeling --- Chapter 5 Social Media --- Emotional Changes in Japanese Blog Space Resulting from the 3.11 Earthquake --- Modeling of ENJYO via process of consensus formation on SNS --- A network structure of emotional interactions in an electronic bulletin board --- Scale-free network topologies with clustering similar to online social networks --- Identifying Colors of Products and Associated Personalized Recommendation Engine in e-Fashion Business
    Pages: Online-Ressource (IX, 346 pages)
    ISBN: 9783319205915
    Language: English
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  • 46
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 26 (1998), S. 57-78 
    ISSN: 0271-2091
    Keywords: parallel processing ; domain partitioning ; hybrid grids ; grid adaptation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A parallel finite volume method for the Navier-Stokes equations with adaptive hybrid prismatic/tetrahedral grids is presented and evaluated in terms of parallel performance. A new method of domain partitioning for complex 3D hybrid meshes is also presented. It is based on orthogonal bisection of a special octree corresponding to the hybrid mesh. The octree is generated automatically and can handle any type of 3D geometry and domain connectivity. One important property of the octree-based partitioning that is exploited is the octree's ability to yield load-balanced partitions that follow the shape of the geometry. This biasing of the octree results in a reduced number of grid elements on the interpartition boundaries and thus fewer data to communicate among processors. Furthermore, the octree-based partitioning gives similar quality of partitions for very different geometries, while requiring minimal user interaction and little computational time. The partitioning method is evaluated in terms of quality of the subdomains as well as execution time. Viscous flow simulations for different geometries are employed to examine the effectiveness of the octree-based partitioning and to test the scalability of parallel execution of the Navier-Stokes solver and hybrid grid adapter on two different parallel systems, the Intel Paragon and the IBM SP2. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 17 Ill.
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  • 47
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 26 (1998), S. 79-100 
    ISSN: 0271-2091
    Keywords: volume-of-fluid method ; free surface flows ; second-order model ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: To improve the numerical analysis of free surface convection and interface reconstruction, both first- and second-order algorithms are developed based on the volume-of-fluid method. The methodology applied to the second-order model is to define the second-order linear curve having both face slopes as near horizontal as possible while satisfying the cell's defined volume fraction.The second-order method is compared with the FLAIR method and the first-order method through simulation of the convection for various sizes of circular liquid shapes and solitary waves. For small curvature of the free surface, e.g. circles with large diameter, linear methods such as the FLAIR method and the first-order method show relatively good predictions. However, for large-curvature configurations, e.g. circles with relatively small diameter or solitary waves, the linear approach shows large distortion of the free surface. In contrast, the second-order model always shows powerful prediction capabilities of free surface convection. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 17 Ill.
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  • 48
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 26 (1998), S. 101-121 
    ISSN: 0271-2091
    Keywords: Riemann solvers ; Eulerian schemes ; detonations ; shock tracking ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper compares several high-resolution schemes for the computation of detonation waves in solid explosives. The essential difficulty in comparison with the usual application domain of these schemes is due to the complexity and variety of the equations of state which are used. The HLLC Riemann solver is used in the context of an Eulerian MUSCL scheme and in conjunction with a shock-tracking scheme. The motivation and justification for the various choices in the building of these schemes are discussed. The accuracy of both schemes, full Eulerian and shock-tracking variant, is clearly demonstrated. In addition, the validity of the results is shown. For one-dimensional applications the shock-tracking scheme is very accurate and relatively simple. For multidimensional applications it is recommended that the full Eulerian version be used. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 16 Ill.
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  • 49
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 26 (1998), S. 177-197 
    ISSN: 0271-2091
    Keywords: unsteady flow ; lifting-line ; numerical computation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper presents the basis of a computational time-marching approach, for large-aspect ratio lifting systems submitted to unsteady motions, using the lifting-line concept. When engineering requires such an approach, quasi-steady ones are currently encountered, which are based on Prandtl's lifting-line approach for steady flows. The results of recent theoretical works on the unsteady lifting-line, based on the matched asymptotic expansion technique, allow one to improve, on sound theoretical foundations, this quasi-steady approach. The proposed approach solves a first-order approximation of the unsteady outer problem for the time-evolution of the spanwise circulation distribution along the lifting-line. It introduces, in the same kind of process as Prandtl's one, for each span section, an unsteady two-dimensional description of the aerofoil behaviour together with a formulation for the three-dimensional unsteady induced velocity on the lifting-line. The approach's validity is examined through a simple numerical implementation for three wing motion cases. Considering the numerical results it produces, it can be stated that the unsteady lifting-line model implementation can be considered as time-consistent, whereas the quasi-steady one cannot. Furthermore, the approach presented here allows large time steps, even for very unsteady wing motions, and compares favourably with some classical results of R. T. Jones. © 1998 John Wiley & Sons, Ltd.
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  • 50
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 26 (1998), S. 217-247 
    ISSN: 0271-2091
    Keywords: puffs and thermals ; turbulence modelling ; jets and plumes ; environmental fluid mechanics ; vortex flow ; added mass ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The time evolution of a line puff, a turbulent non-buoyant element with significant momentum, is studied using the renormalization group (RNG) k-∊ model. The numerical results show that the puff motion is characterized by a vortex pair flow; the computed flow details and scalar mixing characteristics can be described by self-similar relations beyond a dimensionless time of around 30. The added mass coefficient of the puff motion is found to be approximately unity. The predicted puff flow and mixing rate are substantially similar to those obtained from the standard k-∊ model and are well supported by experimental data. The computed scalar field reveals significant secondary concentration peaks trailing behind in the wake of the puff. The present results suggest that the overall mixing rate of a puff is primarily determined by the large-scale motion and that streamline curvature probably plays a minor role. © 1998 John Wiley & Sons, Ltd.
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  • 51
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 26 (1998), S. 251-280 
    ISSN: 0271-2091
    Keywords: turbulence modelling ; eddy viscosity ; second-moment closure ; tidal flows ; finite volume ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper employs one-point, linear eddy viscosity and differential second-moment (DSM) turbulence closures to predict the turbulent characteristics of both rectilinear and circular tidal flows. The numerical scheme is based on a finite volume approach applied to a non-staggered grid such that all flow variables are stored at one and the same set of nodes. Numerical stability is maintained through the implementation of apparent viscosities and source term linearization, which are essential if eddy viscosity terms are absent. A stable algorithm is devised for the Reynolds stresses which includes a non-linear velocity smoothing in order to stabilise the numerical scheme during flow reversal and relaminarization. Favourable agreement with the experimental rectilinear tidal data of Schröder (Tech. Rep. GK55 87/E/16, GKSS-Forshungszentrum Geesthacht, 1983) and McClean (Turbulence and Sediment Transport Measurements in a North Sea Tidal Inlet (the Jade), Springer, New York, 1987, p. 436) is reported. Numerical calculations of circular tidal flows are also presented which were motivated by the preliminary investigations of Davies and Jones (Int. j. numer. meth. fluids,12, 17 (1991)) and Davies (Continental Shelf. Res., 11, 1313 (1991)), who employed the one-equation, k-l, eddy viscosity turbulence model to simulate rectilinear and circular tidal flows. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 323-343 
    ISSN: 0271-2091
    Keywords: mixed convection ; finite volume algorithm ; eccentricity ; Nusselt number ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A computational study is performed on two-dimensional mixed convection in an annulus between a horizontal outer cylinder and a heated, rotating, eccentric inner cylinder. The computation has been done using a non-orthogonal grid and a fully collocated finite volume procedure. Solutions are iterated to convergence through a pressure correction scheme and the convection is treated by Van Leer's MUSCL scheme. The numerical procedure adopted here can easily eliminate the ‘Numerical leakage’ phenomenon of the mixed convection problem whereby strong buoyancy and centrifugal effects are encountered in the case of a highly eccentric annulus. Numerical results have been obtained for Rayleigh number Ra ranging from 7×103 to 107, Reynolds number Re from 0 to 1200 and Prandtl number Pr from 0.01 to 7. The mixed rotation parameter σ (=Ra/PrRe2) varies from ∞ (pure natural convection) to 0.01 with various eccentricities ε. The computational results are in good agreement with previous works which show that the mixed convection heat transfer characteristics in the annulus are significantly affected by σ and ε. The results indicate that the mean Nusselt number Nu increases with increasing Ra or Pr but decreases with increasing Re. In the case of a highly eccentric annulus the conduction effect becomes predominant in the throat gap. Hence the crucial phenomenon on whereby Nu first decreases and then increases can be found with increasing eccentricity. © 1998 John Wiley & Sons, Ltd.
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  • 53
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 303-322 
    ISSN: 0271-2091
    Keywords: hierarchical grids ; quadtrees ; adaptive remeshing ; separated flows ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper describes the use of adaptive hierarchical grids to predict incompressible separated flow at low Reynolds number. The grids consist of a quadtree system of hierarchical Cartesian meshes which are generated by recursive subdivision about seeding points. The governing equations are discretized in collocated primitive variable form using finite volumes and solved using a pressure correction scheme. The mesh is locally adapted at each time step, with panel division or removal dependent on the vorticity magnitude. The resulting grids have fine local resolution and are economical in array size. Results are presented for unidirectional, impulsively started flow past a circular and a square cylinder at various Reynolds numbers up to 5000 and 250 respectively. It is clear that hierarchical meshes may offer gains in efficiency when applied to complex flow domains or strongly sheared flows. However, as expected, the stepped approximation to curved boundaries resulting from the Cartesian quadtree representation adversely affects the accuracy of the results for flow past a circular cylinder. © 1998 John Wiley & Sons, Ltd.
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  • 54
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 443-457 
    ISSN: 0271-2091
    Keywords: direct numerical simulation ; 2D temporal disturbance ; plane Poiseuille flow ; finite difference method ; transient non-linear equation ; stream-function-vorticity equation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A direct numerical scheme is developed to study the temporal amplification of a 2D disturbance in plane Poiseuille flow. The transient non-linear Navier-Stokes equations are applied in a region of wavelength moving with the wave propagation speed. The complex amplitude involved in the perturbation functions is considered as the initial input of the non-linear stability equations. In this study a fully implicit finite difference scheme with five points in the flow direction and three points in the normal direction is developed so that numerical simulation of the amplification of a two-dimensional temporal disturbance in plane Poiseuille flow can be investigated. The growth and decay of the disturbance with time are presented and neutral stability curves which are in good agreement with existing solutions can be determined. The critical conditions as a function of the amplitude A0 of the disturbance are presented. Fixing the wavelength, the Navier-Stokes equations are solved up to Re=10,000 a friction factor increasing with Reynolds number is observed. The 2D non-linear behaviour of the streamfunction, vorticity and velocity components at Re=10,000 are also exhibited. © 1998 John Wiley & Sons, Ltd.
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  • 55
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 485-495 
    ISSN: 0271-2091
    Keywords: capillarity ; free surface ; finite elements ; validation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The mathematical formulation of the dynamics of free liquid surfaces including the effects of surface tension is governed by a non-linear system of elliptic differential equations. The major difficulty of getting unique closed solutions only in trivial cases is overcome by numerical methods. This paper considers transient simulations of liquid-gas menisci in vertical capillary tubes and gaps in the presence of gravity. Therefore the CFD code FIDAP 7.52 based on the Galerkin finite element method (FEM) is used. Calculations using the free surface model are presented for a variety of contact angles and cross-sections with experimental and theoretical verification. The liquid column oscillations are compared for numerical accuracy with a mechanical mathematical model, and the sensitivity with respect to the node density is investigated. The efficiency of the numerical treatment of geometric non-trivial problems is demonstrated by a prismatic capillary. Present restrictions limiting efficient transient simulations with irregularly shaped calculational domains are stated. © 1998 John Wiley & Sons, Ltd.
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  • 56
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 533-556 
    ISSN: 0271-2091
    Keywords: mixed finite elements ; finite volumes ; groundwater flow and transport ; biodegradation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A numerical model for the simulation of flow and transport of organic compounds undergoing bacterial oxygen- and nitrate-based respiration is presented. General assumptions regarding microbial population, bacteria metabolism and effects of oxygen, nitrogen and nutrient concentration on organic substrate rate of consumption are briefly described. The numerical solution techniques for solving both the flow and the transport are presented. The saturated flow equation is discretized using a high-order mixed finite element scheme, which provides a highly accurate estimation of the velocity field. The transport equation for a sorbing porous medium is approximated using a finite volume scheme enclosing an upwind TVD shock-capturing technique for capturing concentration-unsteady steep fronts. The performance and capabilities of the present approach in a bio-remediation context are assessed by considering a set of test problems. The reliability of the numerical results concerning solution accuracy and the computational efficiency in terms of cost and memory requirements are also estimated. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 501-517 
    ISSN: 0271-2091
    Keywords: Multiphase ; turbulent ; finite volumes ; structured grids ; compressible flows ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A numerically fast algorithm has been developed to solve the viscous two-phase flow in an axisymmetric rocket nozzle. A Eulerian-Eulerian approach is employed in the computation to couple the gas-particle flow. Turbulence closure is achieved using a Baldwin-Lomax model. The numerical procedure employs a multistage time-stepping Runge-Kutta scheme in conjunction with a finite volume method and is made computationally fast for the axisymmetric nozzle. The present numerical scheme is applied to compute the flow field inside JPL and AGARD nozzles. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 627-635 
    ISSN: 0271-2091
    Keywords: arbitrary-order boundary element method ; non-singular formulation ; potential problems ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper presents a general direct integral formulation for potential flows. The singularities of Green's functions are desingularized theoretically, using a subtracting and adding back technique, so that Gaussian quadrature or any other numerical integration methods can be applied directly to evaluate all the integrals without any difficulty. When high-order quadrature formulas are applied globally, the number of unknowns can be reduced. Interpolation functions are not necessary for unknown variables in the present paper. Therefore, the present method is much simpler and more efficient than the conventional one. Several numerical examples are calculated and compared satisfactorily with analytical solutions or published results. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 637-655 
    ISSN: 0271-2091
    Keywords: liquid flow ; energy transport ; electron-beam ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A numerical analysis is made of the liquid flow and energy transport in a system to evaporate metals. The energy from an electron-beam heats an axisymmetric metal disk supported by a water-cooled platform. Metal evaporates from the surface of a hot pool of liquid which is surrounded by a shell of its own solid. Flow in the pool is strongly driven by temperature-induced buoyancy and capillary forces, and is located in the transition region between laminar and turbulent flow. The evaporation rate is strongly influenced by the locations of the free boundaries. A modified finite element method is used to calculate the steady state flow and temperature fields coupled with the interface locations. The mesh is structured with spines that stretch and pivot as the interfaces move. The discretized equations are arranged in an ‘arrow’ matrix and are solved using the Newton-Raphson method. The electron-beam power and platform contact resistance are varied for cases involving the evaporation of aluminum. The results reveal the interaction of liquid flow, heat transfer and free interfaces. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 697-712 
    ISSN: 0271-2091
    Keywords: viscoelastic ; boundary conditions ; tube tooling ; cable-coating ; finite elements ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A viscoelastic analysis is presented for model tube tooling, draw-down and combined geometry flows encountered in the cable coating industries. The work investigates the development of stress fields and studies the effect of varying entry flow stress boundary conditions. The analysis takes into account tube tooling and draw-down flow sections individually, and in combination. The flow behaviour of cable-coating grade low density polyethylene is studied assuming a viscoelastic, isothermal flow, and employing a Taylor-Petrov-Galerkin finite element scheme with an exponential Phan-Thien-Tanner constitutive model. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 725-747 
    ISSN: 0271-2091
    Keywords: unsteady two-body interaction ; potential flow theory ; boundary-integral method ; Lagrange's equation of motion ; generalized Taylor's formula ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: On the basis of the potential flow theory, Lagrange's equation of motion is used to study the unsteady ground-effect problem. The forces and moments acting on the moving body are solved in terms of the derivatives of added masses in which the generalized Taylor's formulae are applied. The singular integral equations used to solve the surface source intensities and their derivatives are regularized by the Gauss flux theorem and are therefore amenable to the direct use of the Gaussian quadrature formula. In illustration, the condition of a prolate spheroid moving in the fore-and-aft direction at constant speed past a flat ground with a protrusion is considered. The hydrodynamic forces and moments acting on the moving spheroid are investigated systematically by varying the size of the protrusion and the cruising height of the spheroid. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 791-809 
    ISSN: 0271-2091
    Keywords: open channel ; subcritical and supercritical flows ; TVD schemes ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The Saint Venant equations for modelling flow in open channels are solved in this paper, using a variety of total variation diminishing (TVD) schemes. The performance of second- and third-order-accurate TVD schemes is investigated for the computation of free-surface flows, in predicting dam-breaks and extreme flow conditions created by the river bed topography. Convergence of the schemes is quantified by comparing error norms between subsequent iterations. Automatically calculated time steps and entropy corrections allow high CFL numbers and smooth transition between different conditions. In order to compare different approaches with TVD schemes, the most accurate of each type was chosen. All four schemes chosen proved acceptably accurate. However, there are important differences between the schemes in the occurrence of clipping, overshooting and oscillating behaviour and in the highest CFL numbers allowed by a scheme. These variations in behaviour stem from the different orders and inherent properties of the four schemes. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 771-789 
    ISSN: 0271-2091
    Keywords: three-dimensional numerical method ; hybrid method ; splitting method ; Eulerian-Lagrangian method ; shallow water equations ; sigma co-ordinate transformation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A new efficient numerical method for three-dimensional hydrodynamic computations is presented and discussed in this paper. The method is based on the operator splitting method and combined with Eulerian-Lagrangian method, finite element method and finite difference method. To increase the efficiency and stability of the numerical solutions, the operator splitting method is employed to partition the momentum equations into three parts, according to physical phenomena. A time step is divided into three time substeps. In the first substep, advection and Coriolis force are solved using the explicit Eulerian-Lagrangian method. In the second substep, horizontal diffusion is approximated by implicit FEM in each horizontal layer. In the last substep, the continuity equation is solved by implicit FEM, and vertical diffusion and pressure gradient are discretized by implicit FDM in each nodal column. The stability analysis shows that this method is unconditionally stable. A number of numerical experiments have been performed. The results simulated by the present scheme agree well with analytical solutions and the other documented model results. The method is efficient for 3D shallow water flow computations and fully fits complicated configurations. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 837-850 
    ISSN: 0271-2091
    Keywords: dense gas dispersion ; radiation absorption ; discrete transfer method ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A numerical model is presented for the prediction of thermal radiation absorption in dense gas clouds during accidental release in the atmosphere. The model is based on the discrete transfer method (DT method) that was originally developed for modelling radiation in combustion chambers. The radiation model assumes a number of representative rays of predetermined orientation fired from each of the domain boundaries. Each ray is traced through the domain elements until reaching another boundary where it is terminated. Radiation sources are calculated for each element by performing an energy balance across each element for each ray passing through it. The energy sources recovered are fed into the finite element flow solver for every time step in the energy equation. The model proved accurate, and memory and computer time efficient. It showed that accounting for radiation effects lead to improved predictions. It also showed that in certain scenarios, radiation effects could be predominant. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 877-885 
    ISSN: 0271-2091
    Keywords: B-spline basis ; Galerkin method ; Gauss-Newton method ; mixed formulation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A mixed Galerkin technique with B-spline basis functions is presented to compute two-dimensional incompressible flow in terms of the primitive variable formulation. To circumvent the Babuska-Brezzi stability criterion, the artificial compressibility formulation of the equation of mass conservation is employed. As a result, the diagonal components of the matrix form in the governing equations are not singular. The B-spline basis is used because it is superior to other splines in providing computer solutions to fluid flow problems. One of the advantages of the B-spline basis is that it has excellent approximation properties. Numerical examples of applications of the mixed formulation are presented to demonstrate the convergence characteristics and accuracy of the present formulation. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 927-957 
    ISSN: 0271-2091
    Keywords: multigrid methods ; finite elements ; finite volumes ; semi-coarsening ; numerical analysis ; turbulent flows ; compressible flows ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Extending multigrid concepts to the calculation of complex compressible flow is usually not straightforward. This is especially true when non-embedded grid hierarchies or volume agglomeration strategies are used to construct a gradation of unstructured grids. In this work, a multigrid method for solving second-order PDE's on stretched unstructured triangulations is studied. The finite volume agglomeration multigrid technique originally developed for solving the Euler equations is used (M.-H. Lallemand and A. Dervieux, in Multigrid Methods, Theory, Applications and Supercomputing, Marcel Dekker, 337-363 (1988)). First, a directional semi-coarsening strategy based on Poisson's equation is proposed. The second-order derivatives are approximated on each level by introducing a correction factor adapted to the semi-coarsening strategy. Then, this method is applied to solve the Poisson equation. It is extended to the 2D Reynolds-averaged Navier-Stokes equations with appropriate boundary treatment for low-Reynolds number turbulent flows. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 17-37 
    ISSN: 0271-2091
    Keywords: incompressible Navier-Stokes ; parallel finite element method ; Galerkin approximation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A parallel semi-explicit iterative finite element computational procedure for modelling unsteady incompressible fluid flows is presented. During the procedure, element flux vectors are calculated in parallel and then assembled into global flux vectors. Equilibrium iterations which introduce some ‘local implicitness’ are performed at each time step. The number of equilibrium iterations is governed by an implicitness parameter. The present technique retains the advantages of purely explicit schemes, namely (i) the parallel speed-up is equal to the number of parallel processors if the small communication overhead associated with purely explicit schemes is ignored and (ii) the computation time as well as the core memory required is linearly proportional to the number of elements. The incompressibility condition is imposed by using the artificial compressibility technique. A pressure-averaging technique which allows the use of equal-order interpolations for both velocity and pressure, this simplifying the formulation, is employed. Using a standard Galerkin approximation, three benchmark steady and unsteady problems are solved to demonstrate the accuracy of the procedure. In all calculations the Reynolds number is less than 500. At these Reynolds numbers it was found that the physical dissipation is sufficient to stabilize the convective term with no need for additional upwind-type dissipation. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 1003-1022 
    ISSN: 0271-2091
    Keywords: steady approach flow ; low Reynolds numbers ; 3D simulation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The three-dimensional (3D) unsteady viscous wake of a circular cylinder exposed to a steady approach flow is calculated using a fractional-step finite-difference/spectral-element method. The calculated flow fields at Reynolds numbers of 100 (2D) and 200 (3D) are examined in detail. The flow field at Re = 100 is 2D as expected, while the flow field at Re = 200 has distinct 3D features, with spanwise wavelengths of about 3.75 cylinder diameters. The calculated results produce drag and lift coefficients and Strouhal numbers that agree extremely well with the experimental values. These 3D values at Re = 200 are in better agreement with experimental values than the results of a 2D calculation at Re = 200, which is expected. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 1023-1038 
    ISSN: 0271-2091
    Keywords: three-state anemometry ; velocity field ; particle motion equation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: An application of a new flow measurement technique is described which allows for the non-intrusive simultaneous measurement of flow velocity, density, and viscosity. The viscosity information can be used to derive the flow field temperature. The combination of the three measured variables and the perfect-gas law then leads to an estimate of the flow field thermodynamic pressure. Thus, the instantaneous state of a flow field can be completely described. Three-state anemometry (3SA), a derivative of particle image velocimetry (PIV), which uses a combination of three monodisperse sizes of styrene seeding particles is proposed. A marker seeding is chosen to follow the flow as closely as possible, while intermediate and large seeding populations provide two supplementary velocity fields, which are also dependent on fluid density and viscosity. A simplified particle motion equation, aimed at turbomachinery applications, is then solved over the whole field to provide both density and viscosity data. The three velocity fields can be separated in a number of ways. The simplest and that proposed in this paper is to dye the different populations and view the region of interest through interferometric filters. The two critical aspects needed to enable the implementation of such a technique are a suitable selection of the diameters of the particle populations, and the separation of the velocity fields. There has been extensive work on the seeding particle behaviour which allows an estimate of the suitable particle diameters to be made. A technique is described in this paper to allow the separation of particles in a range of micrometer sized velocity fields through fluorescence (separation through intensity also being possible). Some preliminary results by direct numerical simulation (DNS) of a 3SA image are also presented. The particle sizes chosen were 1 μm and 5 μm, tested on the near-wake flow past a cylinder to investigate viscosity only, assuming uniform flow density. The accuracy of the technique, derived from simulations of swirling flows, is estimated as 0.5% RMS for velocity, 2% RMS for the density and viscosity, and 4% RMS for the temperature estimate. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 1085-1105 
    ISSN: 0271-2091
    Keywords: adaptive ; hybrid grids ; incompressible ; Navier-Stokes ; finite volume ; pressure correction ; 3-D ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Hybrid grids consisting of prisms and tetrahedra are employed for the solution of the 3-D Navier-Stokes equations of incompressible flow. A pressure correction scheme is employed with a finite volume-finite element spatial discretization. The traditional staggered grid formulation has been substituted with a collocated mesh approach which uses fourth-order artificial dissipation. The hybrid grid is refined adaptively in local regions of appreciable flow variations. The scheme operations are performed on an edge-wise basis which unifies treatment of both types of grid elements. The adaptive method is employed for incompressible flows in both single and multiply-connected domains. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 199-215 
    ISSN: 0271-2091
    Keywords: air-conditioning unit ; k-∊ model ; Reynolds stress model ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Details are given of a study to obtain experimental data in an idealized environment for the purpose of evaluating the corresponding computational predictions and which supplement parallel measurements made in actual packaged air-conditioning units. The system consisted of a purpose-built low-speed wind tunnel with a working section constructed to reproduce particular features of the real units. In the experiment, both the mean velocity profiles and turbulence properties of the flow are obtained from triple-hot-wire anemometry measurements. A numerical model, based on finite volume methodology, was used to obtain the solution of the Reynolds-averaged Navier-Stokes equations for incompressible isothermal flow. The Reynolds stress terms in the equations are calculated using the standard k-∊ model and second-moment closure (Reynolds stress) models. The accuracy of the two models was evaluated against the experimental measurements made 10 mm downstream of a baffle. The results show that the standard k-∊ model gave the better agreement except in regions of strong recirculation. © 1997 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 235-247 
    ISSN: 0271-2091
    Keywords: confined explosions ; risk assessment ; CFD ; adaptive mesh refinement ; multiple obstacles ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Explosion hazards constitute a significant practical problem for industry. In response to the need for better-resolved predictions for confined explosions, and particularly with a view to advancing safety cases for offshore oil and gas rigs, an existing unstructured, adaptive mesh, finite volume Reynolds-averaged Navier-Stokes computational fluid dynamics code (originally developed to handle non-combusting turbomachinery flows) has been modified to include a one-equation, eddy break-up combustion model. Two benefits accrue from the use of unstructured, solution-adaptive meshes: first, great geometrical flexibility is possible; second, automatic mesh adaptation allows computational effort to be focused on important or interesting areas of the flow by enhancing mesh resolution only where it is required. In the work reported here, the mesh was adaptively refined to achieve flame front capture, and it is shown that this results in a 10%-33% CPU saving for two-dimensional calculations and a saving of between 57% and 70% for three-dimensional calculations. The geometry of the three-dimensional calculations was relatively simple, and it may be expected that the use of unstructured meshes for truly complex geometries will result in CPU savings sufficient to allow an order-of-magnitude increase in either complexity or resolution. © 1998 John Wiley & Sons, Ltd.
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  • 73
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 281-301 
    ISSN: 0271-2091
    Keywords: Navier-Stokes equations ; SIMPLE algorithm ; algebraic multigrid methods ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The application of standard multigrid methods for the solution of the Navier-Stokes equations in complicated domains causes problems in two ways. First, coarsening is not possible to full extent since the geometry must be resolved by the coarsest grid used. Second, for semi-implicit time-stepping schemes, robustness of the convergence rates is usually not obtained for convection-diffusion problems, especially for higher Reynolds numbers. We show that both problems can be overcome by the use of algebraic multigrid (AMG), which we apply for the solution of the pressure and momentum equations in explicit and semi-implicit time-stepping schemes. We consider the convergence rates of AMG for several model problems and demonstrate the robustiness of the proposed scheme. © 1998 John Wiley & Sons, Ltd.
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  • 74
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 345-364 
    ISSN: 0271-2091
    Keywords: liquid-particle flow ; computational efficiency ; Eulerian-Lagrangian model ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The dispersion of solid particles in a turbulent liquid flow impinging on a centrebody through an axisymmetric sudden expansion was investigated numerically using a Eulerian-Lagrangian model. Detailed experimental measurements at the inlet were used to specify the inlet conditions for two-phase flow computations. The anisotropy of liquid turbulence was accounted for using a second-moment Reynold stress transport model. A recently developed stochastic-probabilistic model was used to enhance the computational efficiency of Lagrangian trajectory computations. Numerical results of the stochastic-probabilistic model using 650 particle trajectories were compared with those of the conventional stochastic discrete-delta-function model using 18 000 particle trajectories. In addition, results of the two models were compared with experimental measurements. © 1998 John Wiley & Sons, Ltd.
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  • 75
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 369-401 
    ISSN: 0271-2091
    Keywords: storm surge ; shallow water model ; grid convergence ; coastal ocean ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The focus of this paper is a systematic determination of the relationship between grid resolution and errors associated with computations of hurricane storm surge. A grid structure is sought that provides the spatial resolution necessary to capture pertinent storm surge physics and does not overdiscretize. A set of numerical experiments simulating storm surge generation over 14 grid discretizations of idealized domains examines the influence of grid spacing, shoreline detail, coastline resolution and characteristics of the meteorological forcing on storm surge computations. Errors associated with a given grid are estimated using a Richardson-based error estimator. Analysis of the magnitude and location of estimated errors indicates that underresolution on the continental shelf leads to significant overprediction of the primary storm surge. In deeper waters, underresolution causes smearing or damping of the inverted barometer forcing function, which in turn results in underprediction of the surge elevation. In order to maintain a specified error level throughout the duration of the storm, the highest grid resolution is required on the continental shelf and particularly in nearshore areas. The disparity of discretization requirements between deep waters and coastal regions is best met using a graded grid. Application of the graded gridding strategy to the hindcast of Hurricane Camille reinforces the necessity of using a grid that has high levels of resolution in nearshore regions and areas of complex coastal geometry. © 1998 John Wiley & Sons, Ltd.
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  • 76
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    International Journal for Numerical Methods in Fluids 27 (1998), S. 127-138 
    ISSN: 0271-2091
    Keywords: compressible flow ; supersonic flows ; aerofoils ; Cauchy/Riemann equations ; Crocco's relation ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In this paper, alternative formulations of the steady Euler equations for conservation of mass, momentum and energy are adopted for the numerical simulation of compressible flows with shock waves. The total enthalpy is assumed to be constant and hence an isentropic density is calculated in terms of the velocity components. Also, the x- and y-momentum equations written in conservation form are combined to yield the tangential and normal momentum equations. For smooth flows the tangential momentum equation reduces to the entropy transport equation, while the normal momentum equation gives the vorticity in terms of the entropy gradient normal to the flow direction (Crocco's relation). Hence the velocity components can be obtained from the continuity equation and normal momentum equation (Cauchy/Riemann equations), while the entropy correction for the density is obtained from the tangential momentum equation (this correction is not needed in the isentropic flow regions). The present formulation can be easily extended to handle variable total enthalpy. Preliminary results are presented for transonic and supersonic flows over aerofoils and the entropy and vorticity effects are clearly identified. © 1998 John Wiley & Sons, Ltd.
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  • 77
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    International Journal for Numerical Methods in Fluids 27 (1998), S. 139-157 
    ISSN: 0271-2091
    Keywords: hydrodynamic stability ; finite element method ; incompressible cavity flow ; Arnold's method ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Numerical methods have been applied to theoretical studies of instability and transition to turbulence. In this study an analysis of the linear stability of incompressible flow is undertaken. By means of the finite element method the two-dimensional base flow is computed numerically over a range of Reynolds numbers and is perturbed with three-dimensional disturbances. The partial differential equations governing the evolution of perturbation are obtained from the non-linear Navier-Stokes equations with a slight compressibility by using linear stability and normal mode analysis. In terms of the finite element discretization a non-singular generalized eigenproblem is formulated from these equations whose solution gives the dispersion relation between complex growth rate and wave number. This study presents stability curves to identify the critical Reynolds number and critical wavelength of the neutral mode and discusses the mechanism of instability. The stability of lid-driven cavity flow is examined. Taylor-Göertler-like vortices in the cavity are obtained by means of reconstruction of three-dimensional flows. © 1998 John Wiley & Sons, Ltd.
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  • 78
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 519-531 
    ISSN: 0271-2091
    Keywords: wavy channel flow ; peristaltic motion ; spectral collocation method ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A numerical procedure is developed for the analysis of flow in a channel whose walls describe a travelling wave motion. Following a perturbation method, the primitive variables are expanded in a series with the wall amplitude as the perturbation parameter. The boundary conditions are applied at the mean surface of the channel and the first-order perturbation quantities are calculated using the pseudospectral collocation method. Although limited by the linear analysis, the present approach is not restricted by the Reynolds number of the flow and the wave number and frequency of the wavy-walled channel. Using the computed wall shear stresses, the positions of flow separation and reattachment are determined. The variations in velocity and pressure with frequency of excitation are also presented. © 1998 John Wiley & Sons, Ltd.
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  • 79
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    International Journal for Numerical Methods in Fluids 27 (1998), S. 207-227 
    ISSN: 0271-2091
    Keywords: directional solidification ; multicomponent alloys ; dendritic monocrystals ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A finite element model of dendritic solidification of multicomponent alloys is presented that includes solutal convection and is an extension of a previously developed model for solidification of binary alloys. The model is applied to simulation of the solidification of ternary and quaternary Ni-based alloys. The role of solutal convection in the macrosegregation and the formation of freckles is analysed. Calculations show the effects of geometry and material properties on the convection patterns and the attendant segregation. © 1998 John Wiley & Sons, Ltd.
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  • 80
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    International Journal for Numerical Methods in Fluids 27 (1998), S. 1-11 
    ISSN: 0271-2091
    Keywords: Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: No Abstract
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  • 81
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 157-186 
    ISSN: 0271-2091
    Keywords: advective transport ; semi-implicit ; conservative ; unconditionally stable ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A one-dimensional scalar transport method which is appropriate for simulations over a wide range of Courant number is described. Von Neumann stability and matrix invertibility are guaranteed for all Courant numbers and the method has less diffusive and dispersive error than simpler implicit methods. It is implemented for vertical scalar transport in a three-dimensional hydrodynamic model, with horizontal transport discretized explicitly. The method is applied and compared with simpler semi-implicit methods in several test cases and used for a simulation of scalar transport in an estuary. © 1998 John Wiley & Sons, Ltd.
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  • 82
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 23-46 
    ISSN: 0271-2091
    Keywords: domain decomposition ; parallel algorithms ; finite element ; Lagrange multipliers ; projected GMRES ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A parallel solver based on domain decomposition is presented for the solution of large algebraic systems arising in the finite element discretization of mechanical problems. It is hybrid in the sense that it combines a direct factorization of the local subdomain problems with an iterative treatment of the interface system by a parallel GMRES algorithm. An important feature of the proposed solver is the use of a set of Lagrange multipliers to enforce continuity of the finite element unknowns at the interface. A projection step and a preconditioner are proposed to control the conditioning of the interface matrix.The decomposition of the finite element mesh is formulated as a graph partitioning problem. A two-step approach is used where an initial decomposition is optimized by non-deterministic heuristics to increase the quality of the decomposition.Parallel simulations of a Navier-Stokes flow problem carried out on a Convex Exemplar SPP system with 16 processors show that the use of optimized decompositions and the preconditioning step are keys to obtaining high parallel efficiencies. Typical parallel efficiencies range above 80%. © 1998 John Wiley & Sons, Ltd.
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  • 83
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 47-72 
    ISSN: 0271-2091
    Keywords: large eddy simulation ; juncture flows ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Large eddy simulation (LES) results are reported for temporally developing solid-solid and solid-rigid-lid juncture flows. A MacCormack-type scheme that is second-order in time, and fourth-order in space for the convective terms and second-order in space for the viscous terms, is used. The simulations are obtained for a low subsonic Mach number. The subgrid-scale stresses (SGS) are modeled using the dynamic modeling procedure. The turbulent flow field generated on a flat-plate boundary layer is used to initialize the juncture flow simulations. The results of the flat-plate boundary layer simulations are validated with experimental and direct numerical simulations (DNS) data. In juncture flow simulations, the presence of an adjacent solid-wall/rigid-lid boundary altered the mean and the turbulent field, setting up gradients in the anisotropy of normal Reynolds stresses resulting in the formation of turbulence-induced secondary vortices. The relative size of these secondary vortices and the distribution of mean and turbulent quantities are in qualitative agreement with the experimental observations for the solid-solid juncture. The overall distribution of the mean and turbulence quantities showed close resemblance between the solid-solid and the solid-rigid-lid junctures; except for the absence of a second vortical region near the rigid-lid boundary. In agreement with the experimental observations, it was found that the normalized anisotropy term exhibited similarity when plotted against the distance from the boundary, regardless of the type of boundary, i.e. solid-wall or rigid-lid. The turbulent kinetic energy increased near the rigid-lid boundary. While the surface normal velocity fluctuations decreased to zero at the rigid-lid boundary, the other two velocity components showed an increase in their energy, which is also consistent with the experimental observations. © 1998 John Wiley & Sons, Ltd.
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  • 84
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 113-128 
    ISSN: 0271-2091
    Keywords: optimal control ; Burgers' equation ; data assimilation ; adjoint model ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In order to use the optimal control techniques in models of geophysical flow circulation, an application to a 1D advection-diffusion equation, the so-called Burgers' equation, is described. The aim of optimal control is to find the best parameters of the model which ensure the closest simulation to the observed values. In a more general case, the continuous problem and the corresponding discrete form are formulated. Three kinds of simulation are realized to validate the method. Optimal control processes by initial and boundary conditions require an implicit discretization scheme on the first time step and a decentered one for the non-linear advection term on boundaries. The robustness of the method is tested with a noised dataset and random values of the initial controls. The optimization process of the viscosity coefficient as a time- and space-dependent variable is more difficult. A numerical study of the model sensitivity is carried out. Finally, the numerical application of the simultaneous control by the initial conditions, the boundary conditions and the viscosity coefficient allows a possible influence between controls to be taken into account. These numerical experiments give methodological rules for applications to more complex situations. © 1998 John Wiley & Sons, Ltd.
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  • 85
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 143-156 
    ISSN: 0271-2091
    Keywords: turbine ; spiral casing ; finite element method ; Galerkin weighted residual technique ; Gauss-Legendre quadrature ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Flow through the spiral casing of a hydraulic turbine was analyzed. Reynolds averaged Navier-Stokes equations were solved using a finite element method. The physical domain was divided into a number of hexahedral elements which are isoparametrically mapped onto standard cubic elements. Numerical integration for the unsteady momentum equation is performed over such hexahedral elements to obtain a provisional velocity field. Compliance with the mass conservation equation and determination of the pressure correction are accomplished through an iterative procedure. The velocity distribution inside the spiral casing corroborates the results available in literature. The static pressure at the midplane generally decreases from the outside wall towards the exit of the spiral casing. © 1998 John Wiley & Sons, Ltd.
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  • 86
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 201-213 
    ISSN: 0271-2091
    Keywords: curved surface ; shallow water ; non-hydrostatic ; spillway ; finite element ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In Part I a detailed derivation of a more general shallow water equation set was developed via a perturbation analysis. A finite element computational model of these more general equations is now constructed and the model behavior is compared with conventional shallow water formulations applied to an outletworks flume. © 1998 John Wiley & Sons, Ltd.
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  • 87
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 225-242 
    ISSN: 0271-2091
    Keywords: turbulent flow ; non-linear turbulence modelling ; secondary flow ; rectangular duct ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Details of the turbulent flow in a 1:8 aspect ratio rectangular duct at a Reynolds number of approximately 5800 were investigated both numerically and experimentally. The three-dimensional mean velocity field and the normal stresses were measured at a position 50 hydraulic diameters downstream from the inlet using laser doppler velocimetry (LDV). Numerical simulations were carried out for the same flow case assuming fully developed conditions by imposing cyclic boundary conditions in the main flow direction. The numerical approach was based on the finite volume technique with a non-staggered grid arrangement and the SIMPLEC algorithm. Results have been obtained with a linear and a non-linear (Speziale) k-ε model, combined with the Lam-Bremhorst damping functions for low Reynolds numbers. The secondary flow patterns, as well as the magnitude of the main flow and overall parameters predicted by the non-linear k-ε model, show good agreement with the experimental results. However, the simulations provide less anisotropy in the normal stresses than the measurements. Also, the magnitudes of the secondary velocities close to the duct corners are underestimated. © 1998 John Wiley & Sons, Ltd.
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  • 88
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 317-336 
    ISSN: 0271-2091
    Keywords: algebraic multigrid ; elementary restriction/prolongation ; minimum residual methods ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: An algebraic multigrid (AMG) scheme is presented for the efficient solution of large systems of coupled algebraic equations involving second-order discrete differentials. It is based on elementary (zero-order) intergrid transfer operators but exhibits convergence rates that are independent of the system bandwidth. Inconsistencies in the coarse-grid approximation are minimised using a global scaling approximation which requires no explicit geometrical information. Residual components of the error spectrum that remain poorly represented in the coarse-grid approximations are reduced by exploiting Krylof subspace methods. The scheme represents a robust, simple and cost-effective approach to the problem of slowly converging eigenmodes when low-order prolongation and restriction operators are used in multigrid algorithms. The algorithm investigated here uses a generalised conjugate residual (GCR) accelerator; it might also be described as an AMG preconditioned GCR method. It is applied to two test problems, one based on a solution of a discrete Poisson-type equation for nodal pressures in a pipe network, the other based on coupled solutions to the discrete Navier-Stokes equations for flows and pressures in a driven cavity. © 1998 John Wiley & Sons, Ltd.
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  • 89
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 293-315 
    ISSN: 0271-2091
    Keywords: Euler equations ; free surface ; gravity waves ; finite volume method ; fractional step method ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A fractional step method is developed for solving the time dependent two-dimensional Euler equations with full non-linear free-surface boundary conditions. The geometry of the free surface is described by a height function, and its evolution is tracked by integrating in time the kinematic boundary conditions based on the free-surface volume flux. The fluid domain is discretised by adapting a time-varying curvilinear grid to all boundaries, including the free surface. Mass and momentum equations are discretised by a conservative finite volume formulation, taking into account the time dependency of the grid. A fractional step type method is developed for integrating the fluid motion in time. The method is applied to a non-linear standing wave in a square container, testing for compliance with mass and energy conservation and comparing computed wave period with other results. Non-linear travelling waves are simulated in channels with either constant depth or varying depth and non-linear wave processes involving both triad interactions and quartet interactions are studied. Results are compared with both experimental data and theoretical results and excellent agreement is found. Interaction of waves and currents is studied. The blocking of waves in an opposing current is simulated and found to show good agreement with theoretical results. The method is intended to be a first step towards a full description of wave dynamics interacting with structures and currents. © 1998 John Wiley & Sons, Ltd.
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  • 90
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 395-418 
    ISSN: 0271-2091
    Keywords: compressible liquid ; Riemann solvers ; approximate Riemann solvers ; Tammann equation of state ; Tait equation of state ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A number of Riemann solvers are proposed for the solution of the Riemann problem in a compressible liquid. Both the Tait and Tammann equations of state are used to describe the liquid. Along with exact Riemann solvers, a detailed description of a primitive variable Riemann solver, a two-shock Riemann solver, a two-rarefaction Riemann solver and an extension to the HLL Riemann solver, namely the HLLC Riemann solver, are presented. It is shown how these Riemann solvers may be implemented into Godunov-type numerical methods. The appropriateness of each of the Riemann solvers for a number of flow situations is demonstrated by applying Godunov's method to some revealing shock tube test problems. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 419-442 
    ISSN: 0271-2091
    Keywords: finite element analysis ; design sensitivity analysis ; optimization ; mold filling ; free surface ; turbulence ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A novel, fully-analytical design sensitivity formulation for transient, turbulent, free surface flows is derived and implemented in the context of finite element analysis. The time-averaged, turbulent form of the Navier-Stokes equations are solved using a mixing length model, in conjunction with the volume of fluid (VOF) method to model the free surface movement. The design derivatives of these governing equations are computed and solved to find the analytical sensitivities of the fluid position, velocity and pressure fields with respect to shape design variables. The computational efficiency produced by evaluating the sensitivities analytically is demonstrated. The design of the runner and gating system of a simple block casting is presented as an example application for using sensitivity information in design. The analytical sensitivity routine is coupled to a numerical optimizer to yield an automated method for optimal design of the casting rigging system. The results produce runner shapes which eliminate mold-gas aspiration. © 1998 John Wiley & Sons, Ltd.
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  • 92
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 477-499 
    ISSN: 0271-2091
    Keywords: natural convection ; tilted cavity ; partial cooling ; storage tanks ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Two-dimensional numerical simulations of laminar natural convection in a partially cooled, differentially heated inclined cavities are performed. One of the cavity walls is entirely heated to a uniformly high temperature (heat source) while the opposite wall is partially cooled to a lower temperature (heat sink). The remaining walls are adiabatic. The tilt angle of the cavity is varied from 0° (heated from left) to -90° (heated from top). The fast false implicit transient scheme (FITS) algorithm, developed earlier by the same authors, is modified to solve the derived variables vorticity-streamfunction formulation. The effects of aspect ratio (AR), sink-source ratio and tilt angle on the average Nusselt number are examined through a parametric study; solutions are obtained for two Grashof numbers, 105 and 107. Flow patterns and isotherms are used to investigate the heat transfer and fluid flow mechanisms inside the cavity. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 523-540 
    ISSN: 0271-2091
    Keywords: non-reflecting boundary conditions ; numerical simulation ; compression wave ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In simulations of propagating blast waves the effects of artificial reflections at open boundaries can seriously degrade the accuracy of the computations. In this paper, a boundary condition based on a local approximation by a plane traveling wave is presented. The method yields small artificial reflections at open boundaries. The derivation and the theory behind these so-called plane-wave boundary conditions are presented. The method is conceptually simple and is easy to implement in two and three dimensions. These non-reflecting boundary conditions are employed in the three-dimensional computational fluid dynamics (CFD) solver FLACS, capable of simulating gas explosions and blast-wave propagation in complex geometries. Several examples involving propagating waves in one and two dimensions, shock tube and an example of a simulation of a propagating blast wave generated by an explosion in a compressor module are shown. The numerical simulations show that artificial reflections due to the boundary conditions employed are negligible. © 1998 John Wiley & Sons, Ltd.
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 565-568 
    ISSN: 0271-2091
    Keywords: fundamental solution method ; integral equation method ; Navier-Stokes equations ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A complete boundary integral formulation for incompressible Navier-Stokes equations with time discretization by operator splitting is developed using the fundamental solutions of the Helmholtz operator equation with different order. The numerical results for the lift and the drag hysteresis associated with a NACA0012 aerofoil oscillating in pitch show good agreement with available experimental data. © 1998 John Wiley & Sons, Ltd.
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  • 95
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 719-736 
    ISSN: 0271-2091
    Keywords: front tracking ; mesh adaptation ; finite element method ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A numerical model is developed for the simulation of moving interfaces in viscous incompressible flows. The model is based on the finite element method with a pseudo-concentration technique to track the front. Since a Eulerian approach is chosen, the interface is advected by the flow through a fixed mesh. Therefore, material discontinuity across the interface cannot be described accurately. To remedy this problem, the model has been supplemented with a local mesh adaptation technique. This latter consists in updating the mesh at each time step to the interface position, such that element boundaries lie along the front. It has been implemented for unstructured triangular finite element meshes. The outcome of this technique is that it allows an accurate treatment of material discontinuity across the interface and, if necessary, a modelling of interface phenomena such as surface tension by using specific boundary elements. For illustration, two examples are computed and presented in this paper: the broken dam problem and the Rayleigh-Taylor instability. Good agreement has been obtained in the comparison of the numerical results with theory or available experimental data. © 1998 John Wiley & Sons, Ltd.
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  • 96
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    International Journal for Numerical Methods in Fluids 28 (1998), S. 601-616 
    ISSN: 0271-2091
    Keywords: turbulence modeling ; CFD ; finite volume method ; vortex shedding ; two-layer approach ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper presents the results of numerical simulations of vortex shedding past a free-standing square cylinder at ReD=22 000, obtained with different turbulence models. Using wall functions, the standard k-ε model is compared with a modification suggested by Kato and Launder (Proc. 9th Symp. Turbulent Shear Flows, Kyoto, 10-4-1 (1993)). In addition, both versions are used in a two-layer approach, in which the flow close to the cylinder is computed with a locally more suitable one-equation turbulence model and only outside the viscous near-wall layer with the two mentioned high-Re model versions. To allow a comparison, the simulations are performed first using the same computational domain and boundary conditions as in previous investigations. Then results are presented that were obtained on a computational domain and with boundary conditions more suitable for a comparison with the experiments. © 1998 John Wiley & Sons, Ltd.
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  • 97
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 1155-1180 
    ISSN: 0271-2091
    Keywords: Navier-Stokes equations ; averaged volume transport equations ; void wave propagation speed ; interfacial effects ; two-phase flow ; finite difference method ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A one-dimensional, time-dependent, isothermal, incompressible, Newtonian fluid, two-phase volume averaging model was developed to study momentum interaction effects in vertical ducts with bubble flow regime. For the evaluation of averaged description, potential inviscid flow around bubbles was considered in order to get closure relationships. The linear dynamic analysis is based on the eigenvalue technique, determining the domain of the hyperbolic behavior and the void fraction wave velocity, which are compared with previous models and experimental data. The solution to the partial differential equations is based on the finite difference technique implicit scheme. These schemes serve to demonstrate the numerical solution procedure. The numerical results are compared with analytical solution and experimental data for void fraction wave propagation. The importance of the surface tension effect in the behavior of the phases in transient conditions is shown. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 8 Ill.
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  • 98
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    International Journal for Numerical Methods in Fluids 26 (1998), S. 1181-1203 
    ISSN: 0271-2091
    Keywords: trapezoidal cylinder ; laminar flow ; Reynolds number ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Characteristics of the developing recirculation region behind a tapered trapezoidal cylinder and its interaction with the separating shear layer from the leading edges were studied numerically for an impulsively started laminar flow. An unsteady stream function-vorticity formulation was used. The Reynolds numbers considered range from 25 to 1000. Pressure contours, surface pressure coefficient, wake length and drag coefficient were studied through the streamline flow field. Main flow and subflow regimes were identified by an analysis of the evolution of the flow characteristics. It was found that typically, for a given trapezoidal cylinder, flow starts with no separation. As time advances, the symmetrical standing zone of recirculation develops aft of the trapezoidal cylinder. The rate of growth in width, length and structure of the aft end eddies depends on the Reynolds number. In time, separated flow from the leading edges of the trapezoidal cylinder also develops and forms growing separation bubbles on the upper and lower inclined surfaces of the trapezoidal cylinder. As time advances, the separation bubbles on the upper and lower inclined surfaces of the cylinder grow towards the downstream regions and eventually merge with the swelling symmetrical eddies aft of the cylinder. This merging of the flows creates a complex flow regime with a disturbed tertiary flow zone near the merging junction. Eventually, depending on the Reynolds number and the tapered angle of the trapezoidal cylinder, the flow develops into a specific category of symmetrical standing recirculatory flow with its own distinct characteristics. Comparisons with the available results of other investigators showed very good agreement. © 1998 John Wiley & Sons, Ltd.
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  • 99
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    International Journal for Numerical Methods in Fluids 27 (1998), S. 33-39 
    ISSN: 0271-2091
    Keywords: error estimation ; Stokes flow ; adaptivity ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: We describe in this paper an algebraic technique for estimating local and pollution errors in finite element approximations of Stokesian flows. © 1998 John Wiley & Sons, Ltd.
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  • 100
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    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 28 (1998), S. 1053-1071 
    ISSN: 0271-2091
    Keywords: turbulence modeling ; internal flow ; flow separation ; shock-boundary layer interaction ; finite volume method ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The existence of shock-turbulent boundary layer interactions lead to very complicated flow phenomena and pose a challenge for numerical simulation. In this paper, two turbulence models, the Baldwin-Lomax (B-L) model and the Johnson-King (J-K) model, which were originally developed for simple external flow simulation, are modified to model complex high-speed internal separated flows. The full Navier-Stokes solver used in this paper is based on a cell-centered finite volume method and multistepping time marching scheme. Both implicit residual smoothing and local time stepping techniques are incorporated to accelerate the convergence rate. To ensure the numerical stability with the present explicit scheme, a point-implicit treatment to the source term in the ordinary differential equation (ODE) of the J-K model has been developed and has proved to be very effective in modeling such a complex flow. An arc-bump channel flow case has been studied. Comparisons of computed results with experimental data show that the present solver, with the modified turbulence models, predicts the shock and the flow separation very well. The J-K model is found to predict the size of the separation bubble with a higher accuracy. © 1998 John Wiley & Sons, Ltd.
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