ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Begrenzungen für die Anwendbarkeit von Preston-Rohren in Kanalströmungen (1970)
    Springer
    Heat and mass transfer 3 (1970), S. 58-62 
    Details
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Abstract Deviations of the velocity distribution near a wall from a universal law cause errors in wall shear stresses determined by means of the Preston tube calibrated in pipe flow. Using the relationship for the velocity distribution presented in [3] and suitable assumptions on Pitot tube errors possible deviations from the Preston tube calibration curve and resulting errors in wall shear stress are calculated and presented as a function of a local geometry parameter for channel flow.
    Notes: Zusammenfassung Abweichungen der Geschwindigkeitsverteilung in Wandnähe von einem universellen Gesetz verursachen Fehler bei der Bestimmung der Wandschubspannung mittels Preston-Rohren, die in der Kreisrohrströmung geeicht wurden. Mit Hilfe des in [3] abgeleiteten Geschwindigkeitsgesetzes und geeigneter Annahmen über die Meßfehler von Pitot-Sonden werden für die Kanalströmung die möglichen Abweichungen von der Preston-Rohr-Eiehkurve und die daraus resultierenden Fehler der zu messenden Wandschubspannung berechnet und in Abhängigkeit eines die örtliche Geometrie kennzeichnenden Parameters dargestellt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01881223
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Berechnung der turbulenten Geschwindigkeitsverteilung und der Wandreibung in konzentrischen Ringspalten (1969)
    Springer
    Heat and mass transfer 2 (1969), S. 36-46 
    Details
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Abstract A generalised relationship has been derived for the eddy viscosity distribution starting from Reichardt's empirical expression valid for the parallel plate geometry and taking account of qualitative trends observed in Brighton's data for the concentric annulus. Using this relationship the turbulent velocity distribution and wall friction is calculated for the annulus. In the numerical calculations use is made only of experimental data pertaining to the circular pipe, which can be considered as a limiting case of the annulus. The theoretical results are in very good agreement with experimental data available.
    Notes: Zusammenfassung Ausgehend von einem empirischen Ansatz vonReichardt für die „scheinbare kinematische Zähigkeit“ der Strömung zwischen parallelen Platten wird nach qualitativer Wertung der experimentellen Ergebnisse vonBrighton ein verallgemeinertes Gesetz für die „scheinbare kinematische Zähigkeit“ formuliert, welches den Reichardtschen Fall als Grenzfall enthält. Mit Hilfe dieses Gesetzes wird die turbulente Geschwindigkeitsverteilung und Wandreibung im konzentrischen Ringspalt berechnet, wobei lediglich vorausgesetzt wird, daß die Strömung im Kreisrohr als Grenzfall des Ringspaltes experimentell bekannt ist. Die theoretischen Ergebnisse werden in ausgezeichneter Weise von den experimentellen Daten verschiedener Autoren bestätigt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00749291
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Berechnung der turbulenten Geschwindigkeitsverteilung und der Wandreibung in unendlich ausgedehnten, parallel angeströmten Stabbündeln (1969)
    Springer
    Heat and mass transfer 2 (1969), S. 246-256 
    Details
    ISSN: 1432-1181
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Description / Table of Contents: Abstract A description is given of a theoretical model for calculating the velocity and shear stress field for axial turbulent flow in rod assemblies with a triangular or rectangular array. The model rests on the assumption that peripheral momentum transport in the fluid takes place by turbulent diffusion only. The radial distributions of velocity and turbulent diffusivity used as input information were those derived for the inner region of concentric annuli [1]. To match the numerical results of the theoretical solution to experimental data obtained for a triangular rod array with a pitchp of 1.08 the assumption had to be made that turbulent diffusion is anisotropic. For the ratio of turbulent diffusivity in peripheral to that in radial direction a value of 10 was found. For this value of the anisotropy factor the flow behaviour was investigated as a function of rod spacing for assemblies with a triangular and rectangular array.
    Notes: Zusammenfassung Es wird ein theoretisches Modell zur Berechnung der turbulenten Strömung parallel zu Stabbündeln in Dreiecks- und Vierecksanordnung beschrieben. Entgegen der allgemein üblichen Annahme, die bisher eine solche Berechnung unmöglich machte, daß der Impulstransport parallel zu den Staboberflächen in Umfangsrichtung im wesentlichen Sekundarströmungen zuzuschreiben sei, wurde angenommen, daß dieser Impulstransport ausschließlich durch turbulente Diffusion erfolgt. Für die bei der Berechnung benötigten Geschwindigkeitsverteilungen und Verteilungen der „scheinbaren kinematischen Zähigkeit“ senkrecht zum benetzten Umfang der Stäbe werden die für die Innenzone konzentrischer Ringspalte in [1] abgeleiteten Gesetze eingesetzt. Um die vorgeschlagene theoretische Lösung experimentellen Ergebnissen für ein Stabbündel in Dreiecksanordnung mit einem relativen Stabmittelpunktsabstand von 1,08 anpassen zu können, mußte eine anisotrope Verteilung der „scheinbaren kinematischen Zähigkeit“ angenommen werden. Für das beschriebene Stabbündel wurde für das Verhältnis der scheinbaren kinematischen Zähigkeiten für den Impulstransport in Umfangs- und radialer Richtung ein Wert von 10 gefunden. Für diesen Wert des Anisotropiefaktors wurde das Strömungsverhalten von Stabbündeln in Dreiecks- und Vierecksanordnung in Abhängigkeit des relativen Stabmittelpunktsabstandes untersucht.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00751358
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The hybrid method, a new method for accurate heat transfer predictions in channels with axially variable heat flux (1973)
    Springer
    Flow, turbulence and combustion 28 (1973), S. 401-418 
    Details
    ISSN: 1573-1987
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A new computation method is presented for the accurate determination of temperature fields and heat transfer characteristics for steady forced convection flow in coolant channels with an arbitrary prescribed wall heat flux. The essential feature of this method is that the fluid region is discretized in the section normal to the flow direction. Energy balances set up for each of the elements yield a system of linear first order differential equations with as a sole independent variable an axial distance parameter. This system of equations is solved analytically using a matrix method. The method is illustrated for the case of laminar flow in flat and circular ducts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00413080
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    SPIKES AND JITTERING IN THE NUMERICAL SOLUTION OF THE PLANETARY BOUNDARY LAYER PROBLEM: CAUSES AND EFFECTS (1997)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 25 (1997), S. 105-121 
    Details
    ISSN: 0271-2091
    Keywords: finite difference approximation ; planetary boundary layer problem ; spikes ; jittering ; 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 experiments performed with all possible combinations of approximations for the equations of a one-dimensional planetary boundary layer model employing a one-equation turbulence closure scheme and a staggered, homogeneous, finite difference grid show that spikes and jittering in the vertical profiles of predicted variables are caused by an inappropriate numerical description of the turbulent kinetic energy equation. Jittering arises when using both moderate and large time steps, while spikes occur for large time steps only. There exist two types of jittering: transient and permanent. The former has a lifetime of about 1 week and occurs with large time steps. Permanent jittering, on the other hand, is observed when using moderate time steps and has a lifetime of more than a 1000 days. Introducing an iterative procedure for the eddy viscosity eliminates spikes and permanent jittering but is unsuccessful in removing transient jittering. It is further found that the transition to instability of the solution can be either a sudden or a gradual one. In the case of a sudden transition no numerical peculiarities are observed, whereas for a gradual transition to instability, jittering is present during the entire transition period. In this sense, jittering may be regarded as a herald of instability. Finally, a combination which employs implicit approximations consistently for all the terms in the model equations, regardless of whether using an implicit or semi-implicit approximation for the Coriolis term, proves to be devoid of any numerical artefacts without the need for introducing the iterative procedure for the eddy viscosity. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 6
    facet.materialart.
    Unknown
    Berechnung der turbulenten Geschwindigkeitsverteilung und der Wandreibung in unendlich ausgedehnten, parallel angeströmten Stabbündeln (1969)
    Springer
    Details
    Publication Date: 1969-12-01
    Print ISSN: 0042-9929
    Electronic ISSN: 1432-1181
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Begrenzungen für die Anwendbarkeit von Preston-Rohren in Kanalströmungen (1970)
    Springer
    Details
    Publication Date: 1970-03-01
    Print ISSN: 0042-9929
    Electronic ISSN: 1432-1181
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    Berechnung der turbulenten Geschwindigkeitsverteilung und der Wandreibung in konzentrischen Ringspalten (1969)
    Springer
    Details
    Publication Date: 1969-03-01
    Print ISSN: 0042-9929
    Electronic ISSN: 1432-1181
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Coastal upwelling prediction with a mixture of neural networks (1998)
    Institute of Electrical and Electronics Engineers
    Details
    Publication Date: 1998-01-01
    Print ISSN: 0196-2892
    Electronic ISSN: 1558-0644
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by Institute of Electrical and Electronics Engineers
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Modeling the thermal surface signature of breaking waves (2001)
    American Geophysical Union
    Details
    Publication Date: 2001-11-15
    Print ISSN: 0148-0227
    Electronic ISSN: 2156-2202
    Topics: Geosciences
    Published by American Geophysical Union
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...