Library

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
  • 11
    Electronic Resource
    Electronic Resource
    Free-convection boundary layer on an isothermal horizontal cylinder (1978)
    Springer
    Zeitschrift für angewandte Mathematik und Physik 29 (1978), S. 871-883 
    Details
    ISSN: 1420-9039
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Description / Table of Contents: Résumé Cette étude considère la convection libre à nombre de Grashof élevé au dessus d'un cylindre horizontal de section circulaire lorsqu'on augmente brusquement sa température. On présente une méthode numérique qui permet de déterminer avec précision la solution des équations instationnaires de la couche limite. Le développement des caractéristiques physiques de l'écoulement est calculé et les résultats sont comparés avec ceux qui ont été déjà obtenus analytiquement pour les petites et grandes valeurs de la variable du temps.
    Notes: Abstract The free convection on a horizontal circular cylinder whose temperature is suddenly increased is studied at large Grashof number. An accurate numerical method is described for determining the solution of the time-dependent boundary-layer equations. The development of the various physical properties of the flow are calculated and compared with their values at small and large times as obtained from the previously obtained analytical solutions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01590813
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Mixed convection similarity solutions on a horizontal surface (1987)
    Springer
    Zeitschrift für angewandte Mathematik und Physik 38 (1987), S. 102-116 
    Details
    ISSN: 1420-9039
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Description / Table of Contents: Zusammenfassung Die Grenzschicht an einer horizontalen Platte mit gemischter Konvektion wird für zwei Fälle untersucht: Für eine ruhende Platte bei gleichförmiger Außenströmung und für eine Platte, die sich kontinuierlich mit konstanter Geschwindigkeit in ihrer eigenen Ebene bewegt, ohne Außenströmung. Für beide Fälle wählen wir ein Potenzgesetz für die Temperaturverteilung entlang der Wand, für welche die Grundgleichungen eine Ähnlichkeitslösung zulassen. In der ersten Problemstellung betrachten wir einen Bereich des Auftriebsparameters, für den zweifache Lösungen existieren. Wir zeigen, wie diese doppelten Lösungen aus einer Bifurkation entstehen und wie der untere Lösungszweig endet, wenn der Auftriebsparameter gegen Null strebt. Für die zweite Problemstellung zeigen wir, daß eine eindeutige Lösung existiert für alle positiven Werte des Auftriebsparameters und daß für negative Werte eine singuläre Lösung mit algebraischem Zerfall erreicht wird.
    Notes: Abstract The mixed convection boundary layer on a horizontal plate is considered for the two separate cases when there is a uniform free stream with the plate held fixed and when there is no outer flow but the plate is moving continuously with a uniform velocity along its length. In both cases we assume that power law temperature distribution on the plate which enables the governing equations to be reduced to similarity form. For the first problem we consider the range of buoyancy parameter for which there are dual solutions, showing how these dual solutions arise from a bifurcation and how the lower branch of solutions terminate as the buoyancy parameter tends to zero. For the second problem we show that there is a unique solution for all positive values of the buoyancy parameter and that for negative values the solution terminates at a singular solution with algebraic decay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00944924
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Steady two-dimensional flow past a normal flat plate (1991)
    Springer
    Zeitschrift für angewandte Mathematik und Physik 42 (1991), S. 584-604 
    Details
    ISSN: 1420-9039
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract A vorticity/stream function formulation is used to obtain a numerical simulation of steady two-dimensional flow of a viscous incompressible fluid past a normal flat plate for a range of Reynolds numbers. A method of Fornberg [J. Fluid Mech. 98, 819 (1980)] is used to determine upstream and downstream boundary conditions on the stream function. Special care is taken in the neighbourhood of the singularities in vorticity at the plate edges and this is very important because any errors introduced are swept downstream and severely affect such quantities as the length and width of the attached eddies. The computed results are compared with those of a laboratory experiment in which a plane strip is drawn through water and ethylene glycol for the range of Reynolds numbers for which the experimental flow is stable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00946178
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    On the use of a Pohlhausen method in three dimensional boundary layers (1977)
    Springer
    Zeitschrift für angewandte Mathematik und Physik 28 (1977), S. 289-299 
    Details
    ISSN: 1420-9039
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Description / Table of Contents: Zusammenfassung Die Arbeit behandelt das dreidimensionale Grenzschichtproblem der Strömung entlang des Inneren an einem Kegel, wobei die Strömung ausserhalb der Grenzschicht durch einen Potentialwirbel entlang der Kegelachse und durch Radialbewegung entlang der Kegel-Generatoren gebildet wird. Die Momenten-Integral-Gleichung wird mit einer Pohlhausen-Methode gelöst. Eine asymptotische Lösung der Grenzschichtgleichung wird dazu benützt, eine gewisse Willkür zu beseitigen, die gewöhnlich bei solchen Methoden auftritt, und gibt zusammen mit der Diskussion von gewissen Grenzbedingungen die Grundlage der Methode.
    Notes: Summary The paper deals with the problem of a three dimensional boundary layer flow on the inner surface of a cone when the flow external to the boundary layer is due to a potential line vortex on the axis of the cone together with a radial flow parallel to the cone generators. The momentum integral equations are solved using a Pohlhausen method. An asymptotic solution of the boundary layer equations is used to overcome the arbitrariness which commonly arises in this type of approach and, together with a discussion of certain other boundary conditions, lays a foundation for the use of the method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01595596
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Singular and non-unique solutions of the boundary-layer equations for the flow due to free convection near a continuously moving vertical plate (1986)
    Springer
    Zeitschrift für angewandte Mathematik und Physik 37 (1986), S. 559-572 
    Details
    ISSN: 1420-9039
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Description / Table of Contents: Zusammenfassung In diesem Artikel wird mittels eines numerischen Verfahrens gezeigt, daß die Grenzschichtgleichungen für die Strömung in der Nähe einer kontinuierlich bewegten vertikalen Platte mit freier Konvektion nicht eindeutig sind. Weiter wird beobachtet, daß es keine Lösungen gibt, wenn die Auftriebskräfte über die Zähigkeitskräfte dominieren. Wenn jedoch die Auftriebskräfte der Plattenbewegung entgegentreten, wird herausgefunden, daß die numerische Lösung zu einer singulären Lösung wird, welche sich vor allen bisher veröffentlichten Resultaten unterscheidet, die durch Lösung der gewöhnlichen nichtlinearen Differentialgleichungen gefunden worden sind, bei denen singuläre und zweifache Lösungen existieren.
    Notes: Abstract In this paper it is shown, using a numerical technique, that the boundary-layer equations for the flow near a continuously moving vertical plate with free convection are not unique. Further it is observed that when the buoyancy forces dominate the viscous forces there are no solutions. However, when the buoyancy forces oppose the motion of the plate, it is found that the numerical solution terminates in a singular manner which is of a different nature to any previously published results which have been obtained by solving non-linear ordinary differential equations where singular and dual solutions exist.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00945430
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Mixed convection in a porous medium produced by a line heat source (1995)
    Springer
    Transport in porous media 18 (1995), S. 1-13 
    Details
    ISSN: 1573-1634
    Keywords: Mixed convection ; thermal plume ; line source ; porous media
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract A boundary-layer analysis is presented for the mixed convection flow which is produced when a horizontal line heat source, which is embedded in an infinite fluid-saturated porous medium, generates heat at a constant rate. It is shown that the governing equations can be non-dimensionalized so that they do not involve any parameters and thus just one solution of the transformed boundary-layer equations is required. Series solutions which are valid both near the line source and far downstream are obtained and compared with the numerical solution of the full boundary-layer equations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00620657
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Mixed Convection Adjacent to a Suddenly Heated Horizontal Circular Cylinder Embedded in a Porous Medium (1998)
    Springer
    Transport in porous media 32 (1998), S. 329-355 
    Details
    ISSN: 1573-1634
    Keywords: mixed convection ; asymptotic expansion techniques impulsively heated horizontal circular cylinder
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract The mixed convection caused when a horizontal circular cylinder is suddenly heated is investigated in the situation when the initial flow past the cylinder is uniform and its direction either upwards or downwards. An analytical series solution, which is valid at small times, is obtained using the matched asymptotic expansions technique. A numerical solution, which is valid at all times and for any values of the Rayleigh and Péclet numbers, is also obtained using a fully implicit finite-difference method. Three different regimes, when either the free or forced convection is dominant or when they have the same order of magnitude, are considered. In the free convection dominated regime, two vortices develop near the sides of the cylinder in both situations of an upward or downward external flow. Comparisons between the analytical and numerical results at small times, as well as a detailed discussion of the evolution of the numerical solution are presented. The numerical results obtained for large Rayleigh, Ra, and Péclet Pe, numbers show that a thermal boundary-layer forms adjacent to the cylinder for any value of the ratio Ra/e. The steady state boundary-layer analysis, similar to that performed by Cheng and Merkin, is analysed in comparison to the numerical solution obtained for large values of Ra and Pe at very large times.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006564031772
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Combined free and forced convection in a porous medium between two vertical walls with viscous dissipation (1990)
    Springer
    Transport in porous media 5 (1990), S. 381-398 
    Details
    ISSN: 1573-1634
    Keywords: Flow in packed channel ; Darcian combined free and forced convection ; fully-developed flow ; multiple solutions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Viscous dissipation effects in the problem of a fully-developed combined free and forced convection flow between two symmetrically and asymmetrically heated vertical parallel walls filled with a porous medium is analyzed. The equation of motion contains the modified Rayleigh number for a porous medium and the small-order viscous dissipation parameter. Particular attention is given to the solutions near the critical Rayleigh numbers at which infinite flow rates are predicted. Information concerning the multiplicity of solutions at critical Rayleigh numbers is also deduced from perturbation solutions of the governing equation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01141992
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Free Convection from a Vertical Plate in a Porous Medium Subjected to a Porous Medium Subjected to a Sudden Change in Surface Heat Flux (1997)
    Springer
    Transport in porous media 26 (1997), S. 205-224 
    Details
    ISSN: 1573-1634
    Keywords: porous medium ; convection ; boundary layer ; transient ; heat flux.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract An analysis is made of the transient free convection from a vertical flat plate which is embedded in a fluid-saturated porous medium. It is assumed that for time $$\overline \tau 〈 0$$ a steady state temperature or velocity has been obtained in the boundary-layer which occurs due to a uniform flux dissipation rate $$q_1^{\prime \prime } $$ . Then at time $$\overline \tau = 0$$ the heat flux on the plate is suddenly changed to $$q_2^{\prime \prime } $$ and maintained at this value for $$\overline \tau 〉 0$$ . An analytical solution has been obtained for the temperature/velocity field for small times in which the transport effects are confined within an inner layer adjacent to the plate. These effects cause a new steady boundary layer. A numerical solution of the full boundary-layer equations is then obtained for the whole transient from $$\overline \tau = 0$$ to the steady state, firstly by means of a step-by-step method and then by a matching technique. The transition between the two distinct solution methods is always observed to occur very near to the turning point of the plate surface temperature, a time at which the fluid temperature is close to its steady state profile. The solution obtained using the step-by-step method shows excellent agreement with the small time analytical solution. Results are presented to illustrate the occurrence of transients from both small and large increases and decreases in the levels of existing energy inputs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006550510374
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    On natural convection from a vertical plate with a prescribed surface heat flux in porous media (1996)
    Springer
    Transport in porous media 22 (1996), S. 181-193 
    Details
    ISSN: 1573-1634
    Keywords: natural convection ; boundary-layers ; surface heat flux
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract This paper presents a theoretical and numerical investigation of the natural convection boundary-layer along a vertical surface, which is embedded in a porous medium, when the surface heat flux varies as (1 +x 2)μ), where μ is a constant andx is the distance along the surface. It is shown that for μ 〉 -1/2 the solution develops from a similarity solution which is valid for small values ofx to one which is valid for large values ofx. However, when μ ⩽ -1/2 no similarity solutions exist for large values ofx and it is found that there are two cases to consider, namely μ 〈 -1/2 and μ = -1/2. The wall temperature and the velocity at large distances along the plate are determined for a range of values of μ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01143514
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...