			Home About us Contact

Convection Flow (convection + flow)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

Unsteady free convection,radiation flow over a vertical wall embedded in a porous medium

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2008
Joaquín Zueco
Abstract A numerical solution for the transient two-dimensional free convection flow of viscous dissipative fluid over an infinite vertical plate through a porous medium bounded, taking into account the thermal radiation, is analysed. The fluid is grey, and acts as a radiation emitting and absorbing (but non-scattering) medium. The influence of the non-dimensional parameters such as the Forchheimer coefficient (Fo), the permeability parameter (P), the Eckert number (Ec) and the radiation parameter (R) on the velocity, temperature, Nusselt number and on the time taken to reach the steady state is studied. The possibility of non-Darcy flow is also analysed. The numerical method employed, network simulation method, is based on an electro-thermal analogy and permits the direct visualization and evolution of the local and/or integrated transport variables (velocities, temperatures and fluxes) at any point or section of the medium. The numerical solutions of this work have been compared with the existing information in the literature with good agreement. Copyright © 2007 John Wiley & Sons, Ltd. [source]

A coupled lattice BGK model for the Boussinesq equations,

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2002
Zhaoli Guo
Abstract In this paper, a thermal lattice BGK model is developed for the Boussinesq incompressible fluids. The basic idea is to solve the velocity field and the temperature field using two independent lattice BGK equations, respectively, and then combine them into one coupled model for the whole system. The porous plate problem and the two-dimensional natural convection flow in a square cavity with Pr=0.71 and various of Rayleigh numbers are simulated using the model. The numerical results are found to be in good agreement with the analytical solutions or those of previous studies. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Stretching a plane surface in a viscoelastic fluid with prescribed skin friction

NUMERICAL METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS, Issue 6 2009
M. Sajid
Abstract A model of forced convection flow due to stretching surface is derived to represent the physical system with prescribed skin friction. To achieve the similar solutions, the partial differential equations are reduced into ordinary differential equations. The analytic solutions of the resulting problems have been obtained by a homotopy analysis method. The convergence of the developed series solution is seen. Finally, the results of velocity, temperature, the stretching velocity, and Nusselt number are analyzed. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009 [source]

Mixed convection flow of non-Newtonian fluid from a slotted vertical surface with uniform surface heat flux

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2009
Rama Subba Reddy Gorla
Abstract In the present paper, the combined convection flow of an Ostwald,de Waele type power-law non-Newtonian fluid past a vertical slotted surface has been investigated numerically. The boundary condition of uniform surface heat flux is considered. The equations governing the flow and the heat transfer are reduced to local non-similarity form. The transformed boundary layer equations are solved numerically using implicit finite difference method. Solutions for the heat transfer rate obtained for the rigid surface compare well with those documented in the published literature. From the present analysis, it is observed that, an increase in , leads to increase in skin friction as well as reduction in heat transfer at the surface. As the power-law index n increases, the friction factor as well as heat transfer increase. Dans cet article, on a étudié numériquement l'écoulement de convection combinée d'un fluide non-newtonien de loi de puissance de type Ostwald-de Waele en aval d'une surface perforée verticale. La condition limite d'un flux de chaleur de surface uniforme est considérée. Les équations gouvernant l'écoulement et le transfert de chaleur sont réduites à la forme de non-similarité locale. Les équations de couche limite transformées sont résolues numériquement par la méthode des différences finies implicites. Les solutions pour la vitesse de transfert de chaleur obtenues pour la surface rigide se comparent bien à celles qui sont décrites dans la littérature scientifique publiée. À partir de la présente analyse, on observe qu'une augmentation de , mène à une augmentation du frottement superficiel ainsi qu'à une réduction du transfert de chaleur à la surface. Lorsque l'indice de loi de puissance n augmente, le facteur de friction et le transfert de chaleur augmentent également. [source]

A general methodology for investigating flow instabilities in complex geometries: application to natural convection in enclosures

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 2 2001
E. Gadoin
Abstract This paper presents a general methodology for studying instabilities of natural convection flows enclosed in cavities of complex geometry. Different tools have been developed, consisting of time integration of the unsteady equations, steady state solving, and computation of the most unstable eigenmodes of the Jacobian and its adjoint. The methodology is validated in the classical differentially heated cavity, where the steady solution branch is followed for vary large values of the Rayleigh number and most unstable eigenmodes are computed at selected Rayleigh values. Its effectiveness for complex geometries is illustrated on a configuration consisting of a cavity with internal heated partitions. We finally propose to reduce the Navier,Stokes equations to a differential system by expanding the unsteady solution as the sum of the steady state solution and of a linear combination of the leading eigenmodes. The principle of the method is exposed and preliminary results are presented. Copyright © 2001 John Wiley & Sons, Ltd. [source]