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  • AERODYNAMICS  (2,983)
  • FLUID MECHANICS AND HEAT TRANSFER  (2,480)
  • 42.75
  • ddc:330
  • 2020-2024  (38)
  • 1985-1989  (5,424)
  • 1950-1954  (39)
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  • 1
    Publication Date: 2024-02-09
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: report , doc-type:report
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  • 2
    Publication Date: 2024-02-09
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: contributiontoperiodical , doc-type:contributionToPeriodical
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  • 3
    Publication Date: 2023-12-20
    Description: Striving to mitigate climate change, the European Union has adopted net-zero greenhouse gas emissions as a target for 2050. In this paper, European chemical industry roadmaps from the past six years are assessed and compared to uncover how the industry envisions its role in the transition to net-zero emissions. The roadmaps are assessed in terms of ambition level, technology and feedstock strategies, investment needs and costs, agency and dependency on other actors, as well as timeline and concretion. Although net-zero pathways are often drawn out in the roadmaps, some also choose to emphasize and argue for less ambitious pathways with emission reductions of only 40-60 %. The roadmaps vary widely in terms of the importance they assign to mechanical and chemical recycling, switching to biogenic carbon and carbon dioxide as feedstock, electrification and hydrogen, and carbon capture and storage. A commonality though, is that low-tech or near-term mitigation pathways such as demand reduction, reuse or material efficiency are seldom included. High investment needs are generally highlighted, as well as the need for policy to create enabling conditions, whereas the agency and responsibility of the chemical industry itself is downplayed. Our analysis highlights that the chemical industry does not yet have a strong and shared vision for pathways to net-zero emissions. We conclude that such a future vision would benefit from taking a whole value chain approach including demand-side options and consideration of scope 3 emissions.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
    Type: article , doc-type:article
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  • 4
    Publication Date: 2024-03-13
    Description: Deutschlands Haushalte werden, zu Beheizungszwecken, zu 70 % leitungsgebunden versorgt: 50 % mit Erdgas und 14 % mit Fernwärme; 5 % mit Elektrizität, davon je die Hälfte noch mit Nachtspeicherheizung, die andere Hälfte mit Wärmepumpen. So war es 2021. So wird es in Zukunft nicht sein, denn Erdgas ist ein Energieträger fossiler Herkunft. Dessen Nutzung geht in den nächsten beiden Jahrzehnten gen Null. Die Frage ist, was das für die Erdgasleitungen in Deutschland bedeutet.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 5
    Publication Date: 2024-03-13
    Description: The petrochemical industry is among the most relevant sectors from an economic, energetic and climate policy perspective. In Western Europe, production occurs in local chemical parks that form strongly connected and densely integrated regional clusters. This paper analyzes the structural characteristics of the petrochemical system in Germany and investigates three particularly distinct clusters regarding their challenges and chances for a transition towards climate-neutrality. For this, feedstock and energy supply, product portfolios and process integration as well as existing transformation activities are examined. We find that depending on their distinct network characteristics and location, unique and complex strategies are to be mastered for every cluster. Despite the many activities underway, none of them seems to have a strategic network to co-create a tailored defossilization strategy for the cluster - which is the core recommendation of this paper to develop.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
    Type: article , doc-type:article
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  • 6
    Publication Date: 2024-03-07
    Description: Demand-side mitigation strategies have been gaining momentum in climate change mitigation research. Still, the impact of different approaches in passenger transport, one of the largest energy demand sectors, remains unclear. We couple a transport simulation model to an energy system optimisation model, both highly disintegrated in order to compare those impacts. Our scenarios are created for the case of Germany in an interdisciplinary, qualitative-quantitative research design, going beyond techno-economic assumptions, and cover Avoid, Shift, and Improve strategies, as well as their combination. The results show that sufficiency - Avoid and Shift strategies - have the same impact as the improvement of propulsion technologies (i.e. efficiency), which is reduction of generation capacities by one quarter. This lowers energy system transformation cost accordingly, but requires different kinds of investments: Sufficiency measures require public investment for high-quality public services, while efficiency measures require individuals to purchase more expensive vehicles at their own cost. These results raise socio-political questions of system design and well-being. However, all strategies are required to unleash the full potential of climate change mitigation.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
    Type: article , doc-type:article
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  • 7
    Publication Date: 2024-04-04
    Description: Die schnelle und umfassende Emissionsminderung in der Energie- und Kreislaufwirtschaft ist der Schlüssel für die Begrenzung der Erderwärmung auf unter 2 °C. In Deutschland werden entsprechende Politiken seit den 1990er-Jahren verfolgt, allerdings erst in jüngster Vergangenheit mit dem notwendigen Nachdruck und der notwendigen Orientierung hin zu mehr Marktmechanismen. Wesentliche Handlungsfelder sind Energieeinsparung und erhöhte Energieeffizienz, Umstieg auf erneuerbare Energien, Bepreisung von Klimagasen sowie eine Reduzierung und Schließung der Stoffkreisläufe. In allen Handlungsfeldern sind Grundlagen geschaffen, es bleibt jedoch der Großteil des Weges noch zu gehen, um Klimaneutralität zu erreichen. Für einen schnellen Fortschritt spielen neben der Überwindung der technischen, ökonomischen und organisatorischen Herausforderungen auch Verteilungsfragen und die Einbettung in internationale Maßnahmen eine zunehmende Rolle.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 8
    Publication Date: 2024-05-13
    Description: Energy performance contracting (EPC) as a market instrument has been effective in promoting energy efficiency worldwide, but it has encountered many insurmountable obstacles in rural energy management. In this study, based on the characteristics of energy management in rural areas, three EPC modes are designed and tested in 24,000 rural households. The test results show that two adapted EPC modes of local government involvement and energy payment directly from the national grid can effectively overcome the barriers encountered in the traditional EPC modes and work well under the economic and social environmental conditions in rural areas. The key to the adaptation of the traditional EPC modes is the introduction of the local government as the third party. Participation of the third party can effectively reduce and remove the barriers and risks and increase the mutual trust between the clients (households) and the energy service companies (ESCOs). Based on the testing results, this study suggests that governmental departments should formulate relevant EPC policies and technical guidelines within the rural context. This research recommends that farmers should not manage their energy services by themselves and it is suggested to out-contracting ESCOs by applying the modes developed and tested by this paper.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
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  • 9
    Publication Date: 2023-10-02
    Description: Die verheerenden Mengen an Abfall am Ende des Lebenszyklus von Produkten zu bewältigen, gilt als eine der größten Herausforderungen auf dem Weg zu einer Circular Economy. Die negativen Folgen, die sich aus dem Missmanagement von Kunststoffabfällen aufgrund fehlender oder nicht funktionierender Abfallwirtschaftsstrukturen in weiten Teilen der Erde ergeben, werden zunehmend deutlich. Bei der Circular Economy als elementarer Lösungsansatz sollen Stoffströme geschlossen und Produktlebenszyklen verlängert werden. Ein Instrument zur Annäherung an dieses Modell ist der Handel mit sogenannten Plastic Credits - ein Mittel, um den Ausbau regionaler Infrastrukturen für die Sammlung und das Recycling von Kunststoffabfällen zu finanzieren. Die Abnehmer von Plastic Credits sind die treibende Kraft hinter dem Mechanismus. Es ist weiterführende Forschung notwendig, insbesondere in Bezug auf die Frage, wie Unternehmen das Instrument der Plastic Credits nutzen und in ihre Gesamtstrategie integrieren. Diese Masterarbeit widmet sich der dabei vorgelagerten Frage: Existieren bestimmte Profile bei Unternehmen, die in Plastic Credits investieren, und lassen sich hierbei spezifische Cluster bilden? Im Rahmen der Beantwortung dieser Frage wurden Expert*innen-Interviews mit Hilfe der qualitativen Inhaltsanalyse nach Mayring ausgewertet. Dabei haben sich drei konkrete Unterfragen ergeben, die sich auf die Motivation, Branchenzugehörigkeit und räumliche Verortung der Abnehmer beziehen. Die Ergebnisse zeigen, dass sich die Abnehmer von Plastic Credits bereits umfangreich mit der Kunststoffabfallproblematik und der damit verbundenen Auswirkung auf die Umwelt beschäftigen. Offen bleibt, inwiefern Maßnahmen zur Vermeidung von neuartigem Kunststoff, der Verbesserung der Recyclingfähigkeit der Produkte oder der Einsatz von Rezyklaten in der Herstellung dem Weg der Kompensation vorangestellt werden. In Bezug auf die Branchenzugehörigkeit legen die Ergebnisse nahe, dass vorrangig Unternehmen, die mit einem erschwerten Rezyklate-Einsatz konfrontiert sind, in Plastic Credits investieren. Welche Auswirkungen Maßnahmen wie die Entbürokratisierung der Zulassungsverfahren für neue Recyclingprozesse oder verpflichtende Anteile an recycelten Materialien in bestimmten Produkten auf die Investition in Plastic Credits haben, wird sich in Zukunft zeigen. Die Analyse der räumlichen Verortung gab Aufschluss darüber, dass zurzeit im Wesentlichen Unternehmen aus dem globalen Norden in Plastic Credits investieren - jedoch verbunden mit dem Ziel, eine Finanzierung aus den Projektländern heraus zu intensivieren.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: masterthesis , doc-type:masterThesis
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  • 10
    Publication Date: 2023-10-02
    Description: Förderbanken vergeben in Deutschland jährlich mindestens 200 Milliarden Euro an Mitteln für Investitionen, die sonst nicht oder sehr viel später umgesetzt werden könnten. Sie arbeiten im öffentlichen Auftrag und richten ihre Tätigkeit an gesellschaftlichen Zielen aus. Diese Ziele haben sich weiterentwickelt. Angesichts von Klimawandel, Energiekrise und den Herausforderungen einer Kreislaufwirtschaft wollen sowohl die Länder als auch die Bundesregierung ihre Förderbanken umbauen. Gerade die Förderbanken der Länder müssen sich darum jetzt bereit machen für die "Weiterentwicklung von Förderbanken zu Transformationsbanken". Für die erfolgreiche Gestaltung dieses gesellschaftlichen Umbruchs brauchen sie Unterstützung. Wie dies gelingt, zeigt dieser Zukunftsimpuls.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: workingpaper , doc-type:workingPaper
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  • 11
    Publication Date: 2023-04-03
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: contributiontoperiodical , doc-type:contributionToPeriodical
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  • 12
    Publication Date: 2023-04-03
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 13
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    München : Siedler
    Publication Date: 2023-04-21
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 14
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    Publication Date: 2023-04-21
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 15
    Publication Date: 2023-04-21
    Description: Ob die Rückführung von industriellen und gewerblichen Sekundärkunststoffen, das heißt von Abfällen bzw. von bereits wiederaufbereiteten Kunststoffrezyklaten, gelingen kann, ist von mehreren Faktoren wie insbesondere den spezifischen Materialeigenschaften, den Mengen, in denen sie anfallen, den aktuellen Marktpreisen (auch gegenüber Neuware) und auch der räumlichen Nähe von Sortier- bzw. Wiederaufbereitungsinfrastruktur abhängig. Trotz eigentlich guter Voraussetzungen für ein werkstoffliches Recycling, gelangen einzelne in Unternehmen anfallende Abfallchargen häufig in eine thermische Verwertung, weil sich ein Recycling wirtschaftlich nicht lohnt. Grund hierfür ist unter anderem, dass der Informationsaustausch zu den oben genannten Faktoren für Unternehmen häufig noch sehr mangelhaft ist. Aktuell in Entwicklung befindliche digitale Plattformen und Applikationen sowie zugehörige Geschäfts- und Betreibermodelle, welche Kunststoffverarbeiter untereinander sowie Wertstofferzeuger und -verwerter vernetzen sollen, können künftig höhere Recyclingquoten ermöglichen und ökologische Einsparpotenziale heben. Der Artikel führt Entwicklungen und Ergebnisse aktueller Forschungsprojekte zu solchen Vernetzungen zusammen, zeigt die aktuelle Situation des werkstofflichen Recyclings von industriellen und gewerblichen Kunststoffabfällen auf und beleuchtet welche Voraussetzungen für eine erfolgreiche Kreislaufführung von industriellen Kunststoffen gegeben sein müssen. Es wird insbesondere analysiert, in welcher Weise digitale Technologien und die durch sie erzielbare Informationstransparenz eine verbesserte Kreislaufwirtschaft bewirken können und in welcher Weise dies Wertschöpfungsnetzwerke räumlich beeinflussen kann.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 16
    Publication Date: 2023-12-05
    Description: The transition to a greener and more circular economy has been a European policy priority for several years. The Circular Economy Action Plan of 2020 underlines the ambition. The following EEA initiatives are meant to support the transition process: - Bellagio Process on circular economy monitoring principles (EPA network); - Enhancement of EEA indicators on circular economy (ETC/WMGE); - Explorative work on novel data streams (FWC); - Co-creation work - knowledge sharing of monitoring experience (ETC/Eionet). The scope of the present task was to report on the co-creation process that was undertaken at the end of 2020. The co-creation process was organised to identify: (i) best practices on monitoring strategies, data sources and target setting; and (ii) areas of circularity measuring and monitoring that remain challenging and require additional investment. The co-creation process partially built on the work done during the Bellagio Process/Initiative which was run in parallel. This ETC report presents and documents the evidence gathered throughout the co- creation process as well as providing a retrospective analysis of the links to the Bellagio Principles.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
    Type: report , doc-type:report
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  • 17
    Publication Date: 2023-03-24
    Description: In der Chemiebranche macht sich mittlerweile die Erkenntnis breit, dass sie zukünftig geschlossene Stoffkreisläufe brauchen wird, wenn sie weiter Gewinne machen will. Doch der Weg dahin ist noch ziemlich weit. Deshalb wird es ohne langfristig angelegte und klare gesetzgeberische Vorgaben nicht gehen.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: contributiontoperiodical , doc-type:contributionToPeriodical
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  • 18
    Publication Date: 2023-05-15
    Description: The Digital Product Passport (DPP) is a concept for collecting and sharing product-related information along the life cycle of a product. DPPs are currently the subject of intense discussion, and various development efforts are being undertaken. These are supported by regulatory activities, especially in the case of the battery passport. The aggregation of product life-cycle data and their respective use, as well as the sharing of these data between companies, entrepreneurs, and other actors in the value chain, is crucial for the creation of a resource-efficient circular economy. Despite the urgent need for such a solution, there is currently little attention given to the digital infrastructure for the creation and handling of the DPPs (i.e., the so-called DPP system). Moreover, there is so far no common understanding of what the requirements for a DPP system are. This is the background and underlying motivation of our paper: we identify the requirements for a DPP system in a structured way, i.e., based on stakeholder involvement and current literature from science and industry. In addition, we compose, categorize, and critically analyze the results, i.e., the list of requirements for DPP systems, in order to identify gaps. Summarized, our research provides insights into the criteria to be considered in the creation of an actual DPP system.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
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  • 19
    Publication Date: 2023-08-02
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
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  • 20
    Publication Date: 2024-01-29
    Description: Fortschreitende Digitalisierung und zunehmende Internationalisierung von Märkten bergen Herausforderungen für Unternehmen mit traditionell geprägten Arbeits- und Fertigungsstrukturen. Um den steigenden Anforderungen gerecht zu werden, sollten in diesen Unternehmen die digitale Arbeitsfähigkeit und Kompetenzen für Agilität ausgebaut werden. Dieser Beitrag beschreibt die Konzeption einer digitalen Plattform zur Steigerung derartiger Kompetenzen in kleinen und mittelständischen Unternehmen (KMU). Die digitale Kompetenzplattform soll insbesondere produzierenden KMU strukturschwacher Regionen helfen, ihre Agilität zu steigern und so zur Innovations- und Zukunftsfähigkeit des Unternehmens beitragen.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 21
    Publication Date: 2023-12-22
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 22
    Publication Date: 2023-12-22
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 23
    Publication Date: 2023-12-22
    Description: Die Transformation der bisher linearen Strukturen von Produktion und Konsum ("take-make-dispose") hin zu einer Circular Economy (CE) - im Sinne einer weiterentwickelten Kreislaufwirtschaft - gilt als zentrales Konzept zur Steigerung der Ressourceneffizienz und Kreislaufführung von Materialien und Produkten, zur Stärkung der Wettbewerbsfähigkeit der einheimischen Industrie sowie zur Schaffung neuer Arbeitsplatzpotenziale. Ziel dieses Forschungsmoduls ist es, die bisherige Umsetzung dieses Konzepts im Rahmen der Nachhaltigkeitsstrategie NRW zu analysieren und durch geeignete Impulse zu begleiten. Durch die Entwicklung eines Leitbilds für eine nachhaltige Circular Economy und zu seiner Messung geeigneter Indikatoren soll das noch an vielen Stellen unscharfe Konzept präzisiert und insbesondere an die spezifischen Ausgangsbedingungen und Herausforderungen von Nordrhein-Westfalen angepasst werden. Dazu sollen Bausteine für ein mittel- und langfristiges Leitbild (2030) entworfen werden, das einen konsistenten Entwicklungspfad für diesen komplexen Transformationsprozess beschreiben soll. Die bestehenden stark abfallwirtschaftlich geprägten Indikatoren zum Thema Kreislaufwirtschaft sollen durch Vorschläge für zusätzliche Indikatoren zur Nachhaltigkeit im Rahmen der Kreislaufwirtschaft (Circular Economy, CE) ergänzt werden.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 24
    Publication Date: 2023-12-22
    Description: Although small and medium-sized enterprises (SMEs) contribute considerably to Germany's carbon emissions, regional savings and cooperative banks - SMEs' most important financiers - hardly consider this aspect in lending to these businesses. However, given Germany's commitment to climate neutrality by 2045, suitable approaches for injecting climate finance into these SME lending processes are greatly required. Against this background, the paper at hand aims to introduce the specific case of regional banks into the debate on green finance and green banking and suggest future research in this context. In discussing the state of research on the peculiarities of regional savings and cooperative banks, we outline the resulting opportunities and limitations for climate impact assessments in SME lending. We argue that while the dual bottom-line orientation of regional banks in Germany precludes them from applying simple positive or negative screenings, their in-depth knowledge about local clients and circumstances enables them to be active and engaging partners for the green transformation of SMEs. Nonetheless, we explain why developing solutions to utilise this knowledge for climate finance by integrating climate impact assessments into routine lending processes remains a particularly challenging task.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 25
    Publication Date: 2023-12-21
    Description: In Deutschland werden jährlich über sieben Millionen gebrauchte Matratzen entsorgt, die überwiegend verbrannt und nur zu einem Bruchteil recycelt werden. Dieser lineare Ansatz belastet die Ressourcen, erhöht die Emissionen und birgt Umweltrisiken. Um diesen Herausforderungen zu begegnen, kann die erweiterte Herstellerverantwortung (Extended Producer Responsibility, EPR) als Instrument zur Umsetzung einer Kreislaufwirtschaft dienen. In dieser Masterarbeit wird daher untersucht, wie ein EPR-System für Matratzen in Deutschland gestaltet sein sollte, um Kreisläufe effizient zu schließen. Gleichzeitig zielt diese Thesis darauf ab, die damit verbundenen Anforderungen und Herausforderungen bei der Umsetzung eines solchen Systems zu identifizieren. Zur Beantwortung der Forschungsfragen wurden mithilfe von Expert*innen-Interviews und einer umfassenden Literaturrecherche drei EPR-Modelle entwickelt und anhand von ausgewählten Kriterien bewertet. Die Ergebnisse der Bewertung ergaben, dass ein Modell präferiert werden sollte, in dem eine sogenannte Producer Responsibility Organisation (PRO) gebündelt die Verantwortung der Hersteller übernimmt. Ein solches System würde unter anderem eine angemessene Kontrolle ermöglichen und Anreize für Forschung und Entwicklung im Bereich der Recyclingtechnologien und des zirkulären Designs der Matratzen schaffen. Obwohl die Datenlage über Altmatratzen und deren Verwertung in Deutschland derzeit noch begrenzt sind und die hier präsentierten Ergebnisse von der gewählten Methodik abhängen, dient diese Masterarbeit als erste Grundlage für die weitere Entwicklung eines EPR-Systems für Matratzen in Deutschland.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: masterthesis , doc-type:masterThesis
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  • 26
    Publication Date: 2023-04-24
    Description: Innovative digital technologies open up new opportun­ ities for small and medium-sized enterprises (SMEs) to improve energy efficiency and energy management behavior. The question is: How far will SMEs be capable of profiting from the benefits of these new technologies? Using technology screening, this study identifies smart metering and mobile energy monitoring as digital technologies best addressing SMEs' specific demands. In addition, potentials and limitations of the technologies are investigated in two qualitative in-depth field trials. Barriers to adopting digitally enabled energy management practices are examined. The results indicate that visualising energy data enables SMEs to pursue new energy management practices for reducing energy consumption and costs (such as peak load analysis). SMEs need extensive guidance to identify and pursue these strategies. In conclusion, an exploratory adoption model for digitally enabled energy management practices is developed. Hypotheses for future experimental studies and policy implications are derived.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
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  • 27
    Publication Date: 2023-12-08
    Description: Die Stärkung der Digitalisierung im Nachhaltigkeitsmanagement und das Schaffen einer einheitlichen sowie konsistenten Datenbasis können Unternehmen maßgeblich unterstützen, steigenden Nachhaltigkeitsanforderungen zu entsprechen und die Transparenz zur Nachhaltigkeit des Wirtschaftens zu gewährleisten. Dieser Beitrag stellt Anforderungen und einen serviceorientierten Ansatz zur Entwicklung einer Plattform für datengestütztes Nachhaltigkeitsmanagement in produzierenden Unternehmen vor.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 28
    Publication Date: 2023-03-24
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: contributiontoperiodical , doc-type:contributionToPeriodical
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  • 29
    Publication Date: 2023-03-24
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
    Type: contributiontoperiodical , doc-type:contributionToPeriodical
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  • 30
    Publication Date: 2023-03-24
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 31
    Publication Date: 2023-03-24
    Description: At the end of March 2022, the European Commission published its new EU Strategy for Sustainable and Circular Textiles. Its ambitious vision is to reduce textile waste, promote circular measures and minimise the negative environmental impacts of the textile industry. But what would a textile industry that keeps textiles in a closed loop look like, and what political conditions would be required in Germany? This Zukunftsimpuls paper by the Wuppertal Institute points to the role that Germany could play in the transformation towards a circular textile industry.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
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  • 32
    Publication Date: 2023-03-24
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 33
    Publication Date: 2023-07-07
    Description: Innerhalb des Projekts "Digitalisierung gestalten - Transformation zur Nachhaltigkeit ermöglichen" werden die besonderen Transformationspotenziale der Digitalisierung herausgearbeitet und für Deutschland am Beispiel der ausgewählten Handlungsfelder Mobilität, Circular Economy sowie Landwirtschaft und Ernährung diskutiert. Dieser Bericht adressiert das Handlungsfeld einer klimaschonenden und ressourceneffizienten Kreislaufwirtschaft, die Circular Economy. Bisher wird Kreislaufwirtschaft dabei vor allem mit Fokus auf Recycling und Wiederverwertung von Materialien diskutiert. Das greift jedoch zu kurz - es muss um die Skalierung von neuen, ressourcenschonenden Geschäftsmodellen und der umfassenden Transformation von Wertschöpfungsketten und Industriestrukturen gehen. Die Analyse zeigt: richtig eingesetzt ist Digitalisierung unverzichtbar für diesen Wandel. Der vorliegende Bericht möchte Anstöße für diesen Weg liefern und neue Impulse für eine klima- und ressourcenschonende Industrietransformation in Deutschland setzen. Der Bericht verarbeitet dabei Ergebnisse eines interdisziplinären Workshops zum Thema "Die digital-ökologische Industrietransformation gestalten - Geschäftsmodelle und politische Rahmenbedingungen für Klima- und Ressourcenschutz" mit Expertinnen und Experten aus Forschung, Zivilgesellschaft, Behörden und Privatunternehmen.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 34
    Publication Date: 2023-07-07
    Description: Das Wirtschafts- und Strukturprogramm für das Rheinische Zukunftsrevier enthält eine Reihe von Zielen, die demonstrieren sollen, wie der European Green Deal modellhaft im Rheinischen Revier bis 2038 umgesetzt werden kann. Das Konzept der "Ressourcenwende" stellt dabei einen Lösungsweg für die erfolgreiche Umsetzung dieser Transformation dar. Das Wuppertal Institut hat vor diesem Hintergrund gemeinsam mit der Prognos AG die vorliegende Studie zu einer regionalen Ressourcenwende im Rheinischen Revier erarbeitet. Das Rheinische Revier ist geprägt durch die Gewinnung, Verstromung und Veredelung von Braunkohle. Darüber hinaus haben sich hier - aufgrund der Nähe zu bedeutenden europäischen Transportwegen und einer zentralen Lage zu wichtigen Märkten in Europa - viele weitere Branchen angesiedelt, wie etwa die Metall-, Chemie- und Aluminiumbranche. Im Hinblick auf den von der Bundesregierung und Nordrhein-Westfalen (NRW) beschlossenen Braunkohleausstieg 2030 und den European Green Deal wird die Notwendigkeit eines Wandels der energie- und ressourcenintensiven Industrien hin zu einer treibhausgasneutralen und ressourcenleichten Wirtschaft im Rheinischen Revier mehr als deutlich. Welchen Fußabdruck hinterlässt das Rheinische Revier, welche innovativen Ressourcenstrategien sollte die Region verfolgen und wie kann dies gemessen werden? Zu dieser Fragestellung haben die Forschenden ein methodisches Konzept einer regionalen Ressourcenwende für das Rheinischen Revier erarbeitet. Die Ressourcenwende selbst begrenzt sich dabei nicht nur auf Primärrohstoffe, sondern nimmt auch die Aspekte wie Bodennutzung bzw. Flächenverbrauch und Biodiversität bzw. Ökosystemleistungen in den Blick und setzt diese in den Kontext eines regionalen Kreislaufwirtschaftssystems.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: German
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  • 35
    Publication Date: 2023-02-08
    Description: Although smart energy technologies (SETs) can fulfill multiple tasks in increasingly decarbonized and digitalized energy systems, market diffusion is still limited. This study investigates which beliefs influence consumers' intention to adopt two smart-energy offerings, whether the rapid growth of the smart home market will now drive SET adoption, and if consumer-driven diffusion will lead to sustainability potentials being realized. Building on UTAUT2, a new theoretical model is proposed, and a consumer acceptance survey was conducted in Germany (n = 700). Results indicate that a growing smart home market will not increase SET adoption and that "adjustable green defaults" should be introduced.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
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  • 36
    Publication Date: 2024-01-18
    Description: The project "Plastic Credits - Financing the Transition to the Global Circular Economy" supports the implementation of a waste management structure in India's rural regions. By that it aims to improve the current waste collection and treatment structures in the pilot regions Goa, Maharashtra, and Kerala. Herein, the project focuses on low value plastics (LVP), and especially multi-layer plastics (MLP), that have no market value. In order to analyze the environmental impacts of the project, an Environmental Impact Assessment (EIA) was conducted. The considered environmental components comprise: greenhouse gas emissions, usage of primary resources, impacts on marine and terrestrial wildlife, standard of living, and economic costs.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
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  • 37
    Publication Date: 2023-05-15
    Description: More than 150 municipal utilities (so-called Stadtwerke) were established in Germany from the beginning of the millennium, bringing the total number of Stadtwerke currently established within the country to approximately 900. With responsibility for more than half of the supply of electricity, gas and heat in Germany, these Stadtwerke play a central role in the transformation of the energy sector, or Energiewende. In addition, due to their local and regional ties, Stadtwerke have a particular role to play in energy politics, the economy and across society. This article focuses on the motives behind, and grounds for, the current wave of newly established Stadtwerke. Further, it discusses the factors that were critical to the successful formation of new Stadtwerke in recent years. The results of our survey indicate that the establishment of municipal Stadtwerke is a suitable measure to implement the energy transition at the local level, whereby the concept of public value has a high level of importance for the local decision-makers. Collaboration and cooperation, as well as a resilience-oriented strategy, are important success factors for new Stadtwerke.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
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  • 38
    Publication Date: 2023-05-15
    Description: The need for a transition towards a circular economy (CE) is evident, as the current economic model is based on the exploitation of far more resources than the planet can replenish sustainably. A significant part of this economic transition is the inception of new, CE-oriented startups and business activities. While business model frameworks (BMF), such as the Business Model Canvas (BMC), were at the center of discussions about structuring business ideas in the beginning of the millennium, the conversation must now shift towards circular BMFs (CBMF). This paper follows the Design Research Methodology (DRM) for an empirical approach to devising a novel CBMF, including expert interviews as well as a first application of the framework with a startup. Throughout this process, a new and innovative tool called Circular Business Framework (CBF) was created and tested based on CE principles.
    Keywords: ddc:330
    Repository Name: Wuppertal Institut für Klima, Umwelt, Energie
    Language: English
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  • 39
    facet.materialart.
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    In:  CASI
    Publication Date: 2005-11-10
    Description: The low-g fluids management group with the Center for Space Construction is engaged in active research on the following topics: gauging; venting; controlling contamination; sloshing; transfer; acquisition; and two-phase flow. Our basic understanding of each of these topics at present is inadequate to design space structures optimally. A brief report is presented on each topic showing the present status, recent accomplishings by our group and our plans for future research. Reports are presented in graphic and outline form.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: First Annual Symposium. Volume 1: Plenary Session; 30 p
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  • 40
    Publication Date: 2011-08-19
    Description: Experimental and theoretical studies have been conducted to determine critical parameters at the onset of nonlinear counterflow in He II below the lambda point of He-4. Critical temperature differences have been measured in porous media for zero net mass flow and for Darcy permeabilities in the order of magnitude range from 10 to the -10th to 10 to the -8th sq cm. The normalized critical temperature gradients, which covered the liquid temperature range of 1.5 K to the lambda temperature, are found to vary with T proportional to the ratio of the superfluid density to the normal fluid density. This liquid temperature dependence appears to be consistent with duct data which are limited at low temperature by a Reynolds number criterion.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Cryogenics (ISSN 0011-2275); 29; 498-502
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  • 41
    Publication Date: 2011-08-19
    Description: An analysis is made based upon the concept that the velocity fluctuations, and therefore, the Reynolds stresses, driven by the instability of the original flow grow until a new stable state is approached. The Reynolds stresses incorporated into the Orr-Sommerfeld equation are coupled with the main flow such that all the imaginary parts of the complex eigenvalues vanish, i.e., the original instability is eliminated. Using this stabilization principle, it is possible to find the Reynolds stresses as well as the mean velocity for plane Poiseuille flow with the Reynolds number slightly higher than the critical.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Mathematical and Computer Modelling (ISSN 0895-7177); 12; 8, 19
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  • 42
    Publication Date: 2011-08-19
    Description: The behavior of the reverse flow ceiling jet against the ventilation flow from 0.58 to 0.87 m/s was investigated in a 1/3 scale model of a wide body aircraft interior. For all tests, strong reverse-flow ceiling jets of hot gases were detected well upstream of the fire. Both thicknesses of the reverse-flow ceiling jet and the smoke layer increased with the fire-crossflow parameter. The thickness of the smoke layer where the smoke flows along the main flow below the reverse-flow ceiling jet was almost twice that of the reverse-flow ceiling jet. Detailed spatial and time-varying temperatures of the gas in the test section were measured, and velocity profiles were also measured using a temperature compensated hot film.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 43
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: Certain theoretical studies of boundary-layer transition are described, based on high Reynolds numbers and with attention drawn to the various nonlinear interactions and scales present. The article concentrates in particular on theories for which the mean-flow profile is completely altered from its original state. Two- and three-dimensional flow theory and conjectures on turbulent-boundary-layer structures are included. Specific recent findings noted, and in qualitative agreement with experiments, are: nonlinear finite-time break-ups in unsteady interactive boundary layers; strong vortex/wave interactions; and prediction of turbulent boundary-layer displacement- and stress sublayer-thicknesses.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
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  • 44
    facet.materialart.
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    Publication Date: 2011-08-19
    Description: Nonequilibrium phenomena in hypersonic flows are examined on the basis of theoretical models and selected experimental data, in an introduction intended for second-year graduate students of aerospace engineering. Chapters are devoted to the physical nature of gas atoms and molecules, transitions of internal states, the formulation of the master equation of aerothermodynamics, the conservation equations, chemical reactions in CFD, the behavior of air flows in nonequilibrium, experimental aspects of nonequilibrium flow, a review of experimental results, and gas-solid interaction. Diagrams, graphs, and tables of numerical data are provided.
    Keywords: AERODYNAMICS
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  • 45
    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 27; 1332-134
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  • 46
    Publication Date: 2011-08-19
    Description: This paper presents the application of a class of multi-grid methods to the solution of the Navier-Stokes equations for two-dimensional laminar flow problems. The methods consists of combining the full approximation scheme-full multi-grid technique (FAS-FMG) with point-, line- or plane-relaxation routines for solving the Navier-Stokes equations in primitive variables. The performance of the multi-grid methods is compared to those of several single-grid methods. The results show that much faster convergence can be procured through the use of the multi-grid approach than through the various suggestions for improving single-grid methods. The importance of the choice of relaxation scheme for the multi-grid method is illustrated.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Institution of Mechanical Engineers, Proceedings, Part C - Journal of Mechanical Engineering Science (ISSN 0954-4062); 203; C4, 1; 255-265
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  • 47
    Publication Date: 2011-08-19
    Description: Rapid distortion theory is applied to study distortion of homogeneous turbulence subject to two different axisymmetric strain modes: the axisymmetric contraction (AC, nozzle-type flow), and the axisymmetric expansion (AE, diffuser-type flow). The paper explores the differences in effects of the two axisymmetric strain modes on the anisotropy of correlations and structures of turbulence; examines the effect of dilatation on the distortion of turbulence; and provides a theoretical background for turbulence model development. It is found that velocity and vorticity fluctuations are enhanced more efficiently by contraction than by expansion; contraction produces much higher anisotropy in velocity and vorticity than expansion; root-mean-square pressure is slightly reduced during contraction, whereas it increases rapidly during expansion; and vortical structures of rodlike shape develop in a contraction flow, while disklike structures develop in an expansion flow. A simple model that reflects the dependence of turbulence evolution on structural parameters such as the Reynolds-stress anisotropy and total strain is proposed, and is shown to outperform all other models for all cases examined, regardless of the mean strain rate.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids A (ISSN 0899-8213); 1; 1541-155
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  • 48
    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 887
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  • 49
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 870-875
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  • 50
    facet.materialart.
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    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 27; 1068-107
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  • 51
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 682-684
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  • 52
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 650-656
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  • 53
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 621-628
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  • 54
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 593-604
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  • 55
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: The introduction of transverse velocity fluctuations into a separated shear layer on an airfoil at high angles of attack is presently demonstrated to be an effective separation-control technique. Airfoil aerodynamic characteristics, including poststall lift and drag as well as maximum lift coefficient and stall angle, all exhibited improvements controlled forcing at 20 deg angle of attack led to an increased spreading of the mean velocity profile, together with increased turbulence activity; separation moved from the leading edge to about 80 percent of chord.
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 27; 820
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  • 56
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 27; 687-693
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  • 57
    Publication Date: 2011-08-19
    Description: Numerical studies of turbulent flow in an axisymmetric 45-deg-expansion combustor and bifurcated diffuser are presented. The Navier-Stokes equations incorporating a k-epsilon model were solved in a nonorthogonal curvilinear coordinate system. A zonal-grid method, where the flow field was divided into several subsections, was developed. This approach permitted different computational schemes to be used in the various zones. In addition, grid generation was made a more simple task. Boundary overlap and interpolating techniques were used, and an adjustment of the flow variables was required to assure conservation of mass flux. Three finite-differencing methods (hybrid, quadratic upwind, and skew upwind) were used to represent the convection terms. Results were compared with existing experimental data. In general, good agreement between predicted and measured values was obtained.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal for Numerical Methods in Fluids (ISSN 0271-2091); 9; 167-183
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  • 58
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 235-240
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  • 59
    Publication Date: 2011-08-19
    Description: A numerical procedure in which the Navier-Stokes equations are discretized using tightly coupled discretizations of pressure derivatives and continuity equations is used here to extend the range of known terminal velocities of gaseous bubbles in liquids well beyond that in previous investigations. Computations performed for Reynolds numbers up to 2000 and Marangoni numbers up to 1000 show only a modest variation of the scaled bubble velocity between 0.16 and 0.5. The bubble velocity is influenced more by the Marangoni number than by the Reynolds number.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Numerical Heat Transfer, Part A: Applications (ISSN 1040-7782); 16; 2, Se
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  • 60
    Publication Date: 2011-08-19
    Description: A numerical analysis is performed on thermocapillary buoyancy convection induced by phase change in a liquid droplet. A finite-difference code is developed using an alternating-direction implicit (ADI) scheme. The intercoupling relation between thermocapillary force, buoyancy force, fluid property, heat transfer, and phase change, along with their effects on the induced flow patterns, are disclosed. The flow is classified into three types: thermocapillary, buoyancy, and combined convection. Among the three mechanisms, the combined convection simulates the experimental observations quite well, and the basic mechanism of the observed convection inside evaporating sessile drops is thus identified. It is disclosed that evaporation initiates unstable convection, while condensation always brings about a stable density distribution which eventually damps out all fluid disturbances. Another numerical model is presented to study the effect of boundary recession due to evaporation, and the 'peeling-off' effect (the removal of the surface layer of fluid by evaporation) is shown to be relevant.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Numerical Heat Transfer, Part A: Applications (ISSN 1040-7782); 16; 2, Se
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  • 61
    Publication Date: 2011-08-19
    Description: Two-dimensional solidification influenced by anisotropic heat conduction has been considered. The interfacial energy balance was derived to account for the heat transfer in one direction (x or y) depending on the temperature gradient in both the x and y directions. A parametric study was made to determine the effects of the Stefan number, aspect ratio, initial superheat, and thermal conductivity ratios on the solidification rate. Because of the imposed boundary conditions, the interface became skewed and sometimes was not a straight line between the interface position at the upper and lower adiabatic walls (spatially nonlinear along the height). This skewness depends on the thermal conductivity ratio k(yy)/k(yx). The nonlinearity of the interface is influenced by the solidification rate, aspect ratio, and k(yy/k(yx).
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Numerical Heat Transfer, Part A: Applications (ISSN 1040-7782); 15; 2, 19; 181-195
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  • 62
    Publication Date: 2011-08-19
    Description: A multiple-time-scale turbulence model of a single point closure and a simplified split-spectrum method is presented. In the model, the effect of the ratio of the production rate to the dissipation rate on eddy viscosity is modeled by use of the multiple-time-scales and a variable partitioning of the turbulent kinetic energy spectrum. The concept of a variable partitioning of the turbulent kinetic energy spectrum and the rest of the model details are based on the previously reported algebraic stress turbulence model. Example problems considered include: a fully developed channel flow, a plane jet exhausting into a moving stream, a wall jet flow, and a weakly coupled wake-boundary layer interaction flow. The computational results compared favorably with those obtained by using the algebraic stress turbulence model as well as experimental data. The present turbulence model, as well as the algebraic stress turbulence model, yielded significantly improved computational results for the complex turbulent boundary layer flows, such as the wall jet flow and the wake boundary layer interaction flow, compared with available computational results obtained by using the standard kappa-epsilon turbulence model.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Numerical Heat Transfer, Part B: Fundamentals (ISSN 1040-7790); 16; 2, 19; 193-211
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  • 63
    Publication Date: 2011-08-19
    Description: The emission from a gray radiating medium is analyzed for transient cooling in surroundings at a low temperature. The medium is rectangular with no variations in the direction normal to the cross section. The integral equation for the transient temperature distribution is solved numerically using a two-dimensional Gaussian integration subroutine. The emissive ability for a rectangle at uniform temperature is compared with that for transient cooling where the temperature distribution of the region has reached a fully developed shape, as shown by a separation of variables solution. The two solutions provide the upper and lower bounds for the emittance of a rectangle during transient cooling. The emittances for various aspect ratios are presented as a function of the mean length of the rectangle and are compared with results for a plane layer and a cylinder.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal of Heat and Mass Transfer (ISSN 0017-9310); 32; 1955-196
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  • 64
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: Calculations for n-decane drops evaporating in a spherical cluster surrounded by unvitiated ambient air at atmospheric pressure were performed using two previously proposed cluster models. Both cluster models predict that turbulent transport effects are more important in the case of small clusters. This is due to the smaller volume to surface ratio and thus to the greater transport of hot unvitiated gas to the drops in order to promote evaporation. The results obtained are compared with those of two turbulent models for each one of the 'trapping factors' and similarity models.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal of Heat and Mass Transfer (ISSN 0017-9310); 32; 2000-200
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  • 65
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 27; 1536-154
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  • 66
    Publication Date: 2011-08-19
    Description: The effects of critical layer nonlinearity are considered on spatially growing oblique instability waves on nominally two-dimensional shear layers between parallel streams. The analysis shows that three-dimensional effects cause nonlinearity to occur at much smaller amplitudes than it does in two-dimensional flows. The nonlinear instability wave amplitude is determined by an integro-differential equation with cubic type nonlinearity. The numerical solutions to this equation are worked out and discussed in some detail. The numerical solutions always end in a singularity at a finite downstream distance.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 207; 97-120
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  • 67
    Publication Date: 2011-08-19
    Description: The effects of critical-layer nonlinearity on spatially growing oblique instability waves on compressible shear layers between two parallel streams are considered. The analysis shows that mean temperature nonuniformities cause nonlinearity to occur at much smaller amplitudes than it does when the flow is isothermal. The nonlinear instability wave growth rate effects are described by an integrodifferential equation which bears some resemblance to the Landau equation, in that it involves a cubic-type nonlinearity. The numerical solutions to this equation are worked out and discussed in some detail. Inviscid solutions always end in a singularity at a finite downstream distance, but viscosity can eliminate this singularity for certain parameter ranges.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 207; 73-96
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  • 68
    Publication Date: 2011-08-19
    Description: Flow characteristics in the vicinity of the flap of a single-slotted airfoil are presented and analyzed. The flow remained attached over the model surfaces, except in the vicinity of the flap trailing edge where a small region of boundary-layer separation extended over the aft 7 percent of flap chord. The airfoil configuration was tested at a Mach number of 0.09 and a chord Reynolds number of 1.8 x 10 to the 6th in the NASA Ames Research Center 7- by 10-Foot Wind Tunnel. The flow was complicated by the presence of a strong, initially inviscid, jet, emanating from the slot between airfoil and flap, and a gradual merging of the main airfoil wake and flap suction-side boundary layer.
    Keywords: AERODYNAMICS
    Type: Experiments in Fluids (ISSN 0723-4864); 7; 8, Se
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  • 69
    Publication Date: 2011-08-19
    Description: A simulation is performed of a passive scalar field convected by a rapidly fluctuating velocity field whose correlation time approaches zero. By using a code proposed in a previous study (Chasnov et al., 1988), the turbulence spectrum of the passive temperature field in the conductive subrange is determined. A theoretical model is proposed which explains the result obtained by representing the transfer of scalar variance by an eddy conductivity, whose correlation time is limited by the correlation time of the velocity field.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physics of Fluids A (ISSN 0899-8213); 1; 1698-170
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  • 70
    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 27; 1557-156
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  • 71
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Thermophysics and Heat Transfer (ISSN 0887-8722); 3; 361-367
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  • 72
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    Publication Date: 2011-08-19
    Description: Long's self-similar vortex is known to have two solutions for each supercritical value of the flow force. Each of those solutions is shown to have a double structure if the flow force is large. The inertial instabilities of one of those large-flow-force limit solutions are investigated, showing that they are related to the instabilities of the Bickley jet in one regime. However, the swirl in the vortex becomes important for long waves, very strongly modifying the sinuous and varicose, Bickley modes. The asymptotic results obtained agree well with the numerical solutions for the sinuous mode, but not for the varicose mode, the difficulty in the latter case being apparently due to mode jumping.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Fluid Mechanics (ISSN 0022-1120); 206; 405-432
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  • 73
    Publication Date: 2011-08-19
    Description: Numerical techniques are developed to solve the Navier-Stokes equations for unsteady incompressible flow. The extension of the finite-difference Galerkin (FDG) method of Stephens et al. (1984) to the continuous-time case in two or three space dimensions is explained, and the numerical implementation of the method is discussed with particular attention to the staggered-MAC-grid primitive-variable discretization, the application of discrete mass balance to avoid problems inherent in FDG schemes, the direct interpretation of the FDG expansion variables as a discrete streamfunction, and a mass-balance approach to two-dimensional problems with throughflow or obstacles. Numerical results are presented graphically for the evolution of asymptotic steady flow in a driven cavity at Reynolds number 400, 1000, or 3200; good agreement with published experimental data is demonstrated, with accurate predictions of secondary-vortex formation from wall bubble recirculations at Reynolds number 1000.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Computational Physics (ISSN 0021-9991); 84; 207-241
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  • 74
    Publication Date: 2011-08-19
    Description: Flow-field measurements of unsteady turbulent flow downstream of a rotating spoked-wheel wake generator were performed in a short-duration light-piston tunnel, and the instantaneous-velocity data were phase averaged based on a signal synchronized with the bar-passing frequency. Mean axial velocities were found to agree well with those obtained from measurements behind a stationary cylinder and to be independent of both Reynolds and bar-passing Strouhal numbers. Reynolds stresses were found to be consistent with related cylinder-wake measurements, but were significantly higher than corresponding measurements obtained in large-scale research turbomachines. Phase-averaged triple velocity correlations were calculated from the digital velocity records, revealing the sign and the magnitude of skewness in the velocity probability density distributions for the two components.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ASME, Transactions, Journal of Turbomachinery (ISSN 0889-504X); 111; 475-482
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  • 75
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: The bifurcation diagram corresponding to the Eckhaus stability curve has been constructed for the one-dimensional Swift-Hohenberg equation in a finite domain. Finite-amplitude solutions with particular spatial wavelength recover linear stability, as predicted by the Eckhaus curve, after a sequence of secondary bifurcations from the branch of solutions with this wavelength. No connectivity between the primary-solution branches is admissible if the stability predicted by this bifurcation diagram is to correspond to the prediction of the Eckhaus analysis. The Eckhaus curve does not exist if nonlinear couplings destroy this pattern. This is demonstrated by analysis of a coupled pair of Swift-Hohenberg equations.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Physical Review Letters (ISSN 0031-9007); 63; 2048-205
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  • 76
    Publication Date: 2011-08-19
    Description: The effects of asymmetry in furnace temperature profile and pulling velocity on the crystal interface shape are demonstrated while neglecting the latent heat of solidification. It is seen that the furnace temperature profile may be varied in order to influence the shape of the melt-crystal interface. An exact thermal analysis is then performed on the Bridgman technique by including the latent heat of solidification as a source term. The exact temperature field required for yielding a flat melt-crystal interface is obtained. The earlier observation regarding the influence of furnace temperature profile on the interface shape is confirmed and a criterion for achieving a flat interface is obtained. Various furnace temperature profiles are selected and their corresponding melt-crystal interface results are presented.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: International Journal of Heat and Mass Transfer (ISSN 0017-9310); 32; 1741-175
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  • 77
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 26; 986-993
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  • 78
    Publication Date: 2011-08-19
    Description: The transonic aspect of helicopter flow analysis is addressed. The equations of motion and their implementations are examined, and the computation of real rotor flows is considered. Nonlifting rotor flows, high-speed hover, high advance ratio lifting rotor flows, and strong blade/vortex interaction computations are discussed.
    Keywords: AERODYNAMICS
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  • 79
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    In:  Other Sources
    Publication Date: 2011-08-19
    Description: Some of the basic finite-difference schemes that can be used to solve the nonlinear equations that describe unsteady inviscid and viscous transonic flow are reviewed. Numerical schemes for solving the unsteady Euler and Navier-Stokes, boundary-layer, and nonlinear potential equations are described. Emphasis is given to the elementary ideas used in constructing various numerical procedures, not specific details of any one procedure.
    Keywords: AERODYNAMICS
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  • 80
    Publication Date: 2011-08-19
    Description: Transient cooling by radiation is analyzed for a cylindrical region filled with axially flowing streams of drops that are becoming solidified. This is of interest for the dissipation of waste heat from orbiting power system in space. The drops absorb, emit, and scatter radiation, and the surroundings are at a lower uniform temperature. The radiative properties are assumed gray, and the scattering is isotropic. The radiating region is a two-phase mixture that remains at the melting temperature of the drops. Its temperature uniformity maintains a high emissive power as energy is lost. This is an advantage over a sensible heat radiator in which the temperature decreases, thereby reducing the emissive power. The results provide the axial length that remains two-phase and the fraction of energy dissipated within this length in which the emissive power has not decreased because of sensible cooling. It is also shown how the radial distribution of the axial velocity of the drops can be modified to increase this energy fraction.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Thermophysics and Heat Transfer (ISSN 0887-8722); 3; 340-344
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  • 81
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    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Journal of Thermophysics and Heat Transfer (ISSN 0887-8722); 3; 233-244
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  • 82
    Publication Date: 2011-08-19
    Description: A number of successful applications of a spectral collocation method extended by a multi-domain patching technique are shown. The multi-domain technique can be used to improve resolution for problems with widely disparate scales, and to reduce the ill-conditioning of the spectral operators for problems in which a large number of points are required for distributed resolution. A new nonreflecting outflow boundary treatment for unsteady transition-to-turbulence simulations is also presented, which relies on the multi-domain technique. The role of multi-domain in improving the efficiency of such calculations is discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Applied Numerical Mathematics (ISSN 0168-9274); 6; 123-139
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  • 83
    Publication Date: 2011-08-19
    Description: Spectral element methods are high-order weighted residual techniques based on spectral expansions of variables and geometry for the Navier-Stokes (NS) and transport equations. Here, practical aspects of these methods and their efficient implementation are examined, and several examples of flows in truly complex geometries are presented. The spectral element discretization for NS equations is introduced, and the convergence of the method is addressed. An efficient data management scheme is discussed in the context of parallel processing computations. The method is validated by comparing the spectral element solutions with the exact eigensolutions for the Orr-Sommerfeld equations in two and three dimensions. Computer-aided flow visualizations are presented for an impulsive flow past a sharp edge wedge. Three-dimensional states of channel flow disrupted by an array of cylindrical eddy promoters are studied, and the results of a direct simulation of the turbulent flow in a plane channel are presented.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Applied Numerical Mathematics (ISSN 0168-9274); 6; 85-105
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  • 84
    Publication Date: 2011-08-19
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: AIAA Journal (ISSN 0001-1452); 27; 1707-171
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  • 85
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 27; 1752-176
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  • 86
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 27; 1673-167
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  • 87
    Publication Date: 2013-08-31
    Description: A description of the Axial Flow Turbine Research Facility (AFTRF) being built at the Turbomachinery Laboratory of the Pennsylvania State University is presented. The purpose of the research to be performed in this facility is to obtain a better understanding of the rotor/stator interaction, three dimensional viscous flow field in nozzle and rotor blade passages, spanwise mixing and losses in these blade rows, transport of wake through rotor passage, and unsteady aerodynamics and heat transfer of rotor blade row. The experimental results will directly feed and support the analytical and the computational tool development. This large scale low speed facility is heavily instrumented with pressure and temperature probes and has provision for flow visualization and laser Doppler anemometer measurement. The facility design permits extensive use of the high frequency response instrumentation on the stationary vanes and more importantly on the rotating blades. Furthermore it facilitates detailed nozzle wake, rotor wake, and boundary layer surveys. The large size of the rig also has the advantage of operating at Reynolds numbers representative of the engine environment.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA. Lewis Research Center, Structural Integrity and Durability of Reusable Space Propulsion Systems; p 223-236
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  • 88
    Publication Date: 2013-08-31
    Description: A quasi-three-dimensional analysis has been developed for unsteady rotor-stator interaction in turbomachinery. The analysis solves the unsteady Euler or thin-layer Navier-Stokes equations in a body-fitted coordinate system. It accounts for the effects of rotation, radius change, and stress-surface thickness. The Baldwin-Lomax eddy-viscosity model is used for turbulent flows. The equations are integrated in time using an explicit four-stage Runge-Kutta scheme with a constant time step. Implicit residual smoothing is used to increase the stability limit of the time-accurate computations. The scheme is described, and stability and accuracy analyses are given.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Structural Integrity and Durability of Reusable Space Propulsion Systems; p 237-246
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  • 89
    Publication Date: 2013-08-31
    Description: A 3-D model was developed for simulating multistage turbomachinery flows using supercomputers. This average passage flow model described the time averaged flow field within a typical passage of a bladed wheel within a multistage configuration. To date, a number of inviscid simulations were executed to assess the resolution capabilities of the model. Recently, the viscous terms associated with the average passage model were incorporated into the inviscid computer code along with an algebraic turbulence model. A simulation of a stage-and-one-half, low speed turbine was executed. The results of this simulation, including a comparison with experimental data, is discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: Structural Integrity and Durability of Reusable Space Propulsion Systems; p 247-251
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  • 90
    Publication Date: 2013-08-31
    Description: The flight testing conducted over the past 10 years in the NASA laminar-flow control (LFC) will be reviewed. The LFC program was directed towards the most challenging technology application, the high supersonic speed transport. To place these recent experiences in perspective, earlier important flight tests will first be reviewed to recall the lessons learned at that time.
    Keywords: AERODYNAMICS
    Type: Transonic Symposium: Theory, Application and Experiment, Volume 2; p 59-104
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  • 91
    Publication Date: 2013-08-31
    Description: Although most of the laminar flow airfoils recently developed at the NASA Langley Research Center were intended for general aviation applications, low-drag airfoils were designed for transonic speeds and wind tunnel performance tested. The objective was to extend the technology of laminar flow to higher Mach and Reynolds numbers and to swept leading edge wings representative of transport aircraft to achieve lower drag and significantly improved operation costs. This research involves stabilizing the laminar boundary layer through geometric shaping (Natural Laminar Flow, NLF) and active control involving the removal of a portion of the laminar boundary layer (Laminar-Flow Control, LFC), either through discrete slots or perforated surface. Results show that extensive regions of laminar flow with large reductions in skin friction drag can be maintained through the application of passive NLF boundary-layer control technologies to unswept transonic wings. At even greater extent of laminar flow and reduction in the total drag level can be obtained on a swept supercritical airfoil with active boundary layer-control.
    Keywords: AERODYNAMICS
    Type: Transonic Symposium: Theory, Application and Experiment, Volume 2; p 105-145
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  • 92
    Publication Date: 2013-08-31
    Description: Aerodynamic forces and moments for a slender wing-body configuration are summarized from an investigation in the Langley National Transonic Facility (NTF). The results include both longitudinal and lateral-directional aerodynamic properties as well as slideslip derivatives. Results were selected to emphasize Reynolds number effects at a transonic speed although some lower speed results are also presented for context. The data indicate nominal Reynolds number effects on the longitudinal aerodynamic coefficients and more pronounced effects for the lateral-directional aerodynamic coefficients. The Reynolds number sensitivities for the lateral-directional coefficients were limited to high angles of attack.
    Keywords: AERODYNAMICS
    Type: Transonic Symposium: Theory, Application and Experiment, Volume 2; p 41-58
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  • 93
    Publication Date: 2013-08-31
    Description: The objective is to provide useful engineering formulations and to instill a modest degree of physical understanding of the phenomena governing convective aerodynamic heating at high flight speeds. Some physical insight is not only essential to the application of the information presented here, but also to the effective use of computer codes which may be available to the reader. Given first is a discussion of cold-wall, laminar boundary layer heating. A brief presentation of the complex boundary layer transition phenomenon follows. Next, cold-wall turbulent boundary layer heating is discussed. This topic is followed by a brief coverage of separated flow-region and shock-interaction heating. A review of heat protection methods follows, including the influence of mass addition on laminar and turbulent boundary layers. Next is a discussion of finite-difference computer codes and a comparison of some results from these codes. An extensive list of references is also provided from sources such as the various AIAA journals and NASA reports which are available in the open literature.
    Keywords: AERODYNAMICS
    Type: Nielsen Engineering and Research, Inc., Missile Aerodynamics: NEAR Conference on Missile Aerodynamics; 64 p
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  • 94
    Publication Date: 2013-08-31
    Description: A co-operative testing program is in progress between the Langley Research Center (NASA) and the National Aeronautical Establishment (NAE, Canada) to validate two different techniques of airfoil testing at transonic speeds. The procedure employed is to test the same airfoil model in the NAE two-dimensional tunnel and the Langley 0.3-m Transonic Cryogenic Tunnel (0.3-m TCT). The airfoil model used in testing was CAST-10-2/DOA-2 super-critical airfoil. The Langley 0.3-m TCT has a relatively small cross section of 13 in x 13 in, giving a (h/c) ratio of 1.44 for the same 9 in chord model. The approach employed in the 0.3-m TCT aims towards eliminating the wall effects by using active walls. The top and bottom walls are flexible. By changing the wall shapes during a test in an iterative manner, the wall interference effects are reduced. The method employed to change the wall shapes is the adaptive wall technique. The current test program provided an opportunity to validate the adaptive wall technique in the 0.3-m TCT. The relatively long chord airfoil represents a severe test case to test the efficacy of the adaptive wall technique under cryogenic conditions. The program also involved removal of side wall boundary-layer thus increasing the complexity of the wall adaptation technique. This paper deals with some salient results obtained regarding repeatability of test data and possible residual interference effects.
    Keywords: AERODYNAMICS
    Type: CAST-10-2(DOA 2 Airfoil Studies Workshop Results; p 213-231
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  • 95
    Publication Date: 2013-08-31
    Description: A multiphase turbulence closure model is presented which employs one transport equation, namely the turbulence kinetic energy equation. The proposed form of this equation is different from the earlier formulations in some aspects. The power spectrum of the carrier fluid is divided into two regions, which interact in different ways and at different rates with the suspended particles as a function of the particle-eddy size ratio and density ratio. The length scale is described algebraically. A mass/time averaging procedure for the momentum and kinetic energy equations is adopted. The resulting turbulence correlations are modeled under less retrictive assumptions comparative to previous work. The closures for the momentum and kinetic energy equations are given. Comparisons of the predictions with experimental results on liquid-solid jet and gas-solid pipe flow show satisfactory agreement.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA, Marshall Space Flight Center, Constitutive Relationships and Models in Continuum Theories of Multiphase Flows; p 147-162
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  • 96
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    In:  CASI
    Publication Date: 2013-08-31
    Description: Generally, two types of theory are used to describe the field equations for suspensions. The so-called postulated equations are based on the kinetic theory of mixtures, which logically should give reasonable equations for solutions. The basis for the use of such theory for suspensions is tenuous, though it at least gives a logical path for mathematical arguments. It has the disadvantage that it leads to a system of equations which is underdetermined, in a sense that can be made precise. On the other hand, the so-called averaging theory starts with a determined system, but the very process of averaging renders the resulting system underdetermined. A third type of theory is proposed in which the kinetic theory of gases is used to motivate continuum equations for the suspended particles. This entails an interpretation of the stress in the particles that is different from the usual one. Classical theory is used to describe the motion of the suspending medium. The result is a determined system for a dilute suspension. Extension of the theory to more concentrated systems is discussed.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA, Marshall Space Flight Center, Constitutive Relationships and Models in Continuum Theories of Multiphase Flows; p 57-64
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  • 97
    Publication Date: 2013-08-31
    Description: The two-dimensional (2-D) and three-dimensional Navier-Stokes equations are solved for flow over a NAE CAST-10 airfoil model. Recently developed finite-volume codes that apply a multistage time stepping scheme in conjunction with steady state acceleration techniques are used to solve the equations. Two-dimensional results are shown for flow conditions uncorrected and corrected for wind tunnel wall interference effects. Predicted surface pressures from 3-D simulations are compared with those from 2-D calculations. The focus of the 3-D computations is the influence of the sidewall boundary layers. Topological features of the 3-D flow fields are indicated. Lift and drag results are compared with experimental measurements.
    Keywords: AERODYNAMICS
    Type: CAST-10-2(DOA 2 Airfoil Studies Workshop Results; p 233-258
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  • 98
    Publication Date: 2013-08-31
    Description: An experimental Adaptive Wall Test Section (AWTS) process is described. Comparisons of the ONERA T2 and the 0.3-m TCT (transonic cryogenic tunnel) AWTS data for the ONERA CAST-10 airfoil are presented. Most of the 0.3-m TCT data is new and preliminary and no sidewall boundary layer control is involved. No conclusions are given.
    Keywords: AERODYNAMICS
    Type: CAST-10-2(DOA 2 Airfoil Studies Workshop Results; p 137-153
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  • 99
    Publication Date: 2013-08-31
    Description: The transonic airfoil CAST 10-2/DOA 2 was investigated in several major transonic wind tunnels at Reynolds numbers ranging from Re=1.3 x 10(exp 6) to 45 x 10(exp 6) at ambient and cryogenic temperature conditions. The main objective was to study the degree and extent of the effects of Reynolds number on both the airfoil aerodynamic characteristics and the interference effects of various model-wind-tunnel systems. The initial analysis of the CAST 10-2 airfoil results revealed appreciable real Reynolds number effects on this airfoil and showed that wall interference can be significantly affected by changes in Reynolds number thus appearing as true Reynolds number effects.
    Keywords: AERODYNAMICS
    Type: CAST-10-2(DOA 2 Airfoil Studies Workshop Results; p 47-60
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  • 100
    Publication Date: 2013-08-31
    Description: The vaporization of a droplet, interacting with its neighbors in a non-dilute spray environment is examined as well as a vaporization scaling law established on the basis of a recently developed theory of renormalized droplet. The interacting droplet consists of a centrally located droplet and its vapor bubble which is surrounded by a cloud of droplets. The distribution of the droplets and the size of the cloud are characterized by a pair-distribution function. The vaporization of a droplet is retarded by the collective thermal quenching, the vapor concentration accumulated in the outer sphere, and by the limited percolative passages for mass, momentum and energy fluxes. The retardation is scaled by the local collective interaction parameters (group combustion number of renormalized droplet, droplet spacing, renormalization number and local ambient conditions). The numerical results of a selected case study reveal that the vaporization correction factor falls from unity monotonically as the group combustion number increases, and saturation is likely to occur when the group combustion number reaches 35 to 40 with interdroplet spacing of 7.5 diameters and an environment temperature of 500 K. The scaling law suggests that dense sprays can be classified into: (1) a diffusively dense cloud characterized by uniform thermal quenching in the cloud; (2) a stratified dense cloud characterized by a radial stratification in temperature by the differential thermal quenching of the cloud; or (3) a sharply dense cloud marked by fine structure in the quasi-droplet cloud and the corresponding variation in the correction factor due to the variation in the topological structure of the cloud characterized by a pair-distribution function of quasi-droplets.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: NASA, Marshall Space Flight Center, Constitutive Relationships and Models in Continuum Theories of Multiphase Flows; p 65-101
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