Free Convection Induced by a Vertical Wavy Surface With Uniform Heat Flux in a Porous Medium

1995 ◽  
Vol 117 (2) ◽  
pp. 547-550 ◽  
Author(s):  
D. A. S. Rees ◽  
I. Pop
Author(s):  
Bernardo Buonomo ◽  
Oronzio Manca ◽  
Sergio Nardini ◽  
Guy Lauriat

A numerical investigation on a single slot jet impinging in a porous parallel-plate channel containing an air-saturated high permeability porous medium is accomplished. The wall opposite the slot jet is partially heated at uniform heat flux and the buoyancy effects are taken into account. The fluid flow is assumed two dimensional, laminar and steady. The porous medium is modeled using the Brinkman–Forchheimer-extended Darcy model and the Boussinesq approximation. The local thermal non-equilibrium (LTNE) hypothesis is invoked. The results are discussed in terms of streamlines, fluid and solid phase temperature fields, wall temperature profiles and local and average Nusselt numbers. The porous medium allows a more significant heat transfer close to the end of the heated part of the plate. For low Peclet numbers, forced flow and natural convection are opposite and the mean Nusselt number shows a decrease in heat transfer, whereas they are aiding for high Peclet numbers. Porosity effects on the mean Nusselt numbers were found weak.


2007 ◽  
Vol 129 (10) ◽  
pp. 1403-1407 ◽  
Author(s):  
Mamun Molla ◽  
Anwar Hossain ◽  
Lun-Shin Yao

A natural-convection boundary layer along a vertical complex wavy surface with uniform heat flux has been investigated. The complex surface studied combines two sinusoidal functions, a fundamental wave and its first harmonic. Using a method of transformed coordinates, the boundary-layer equations are mapped into a regular and stationary computational domain. The transformed equations can then be solved straightforwardly by any number of numerical methods designed for regular and stationary geometries. In this paper, an implicit finite-difference method is used. The results were readily obtained on a personal computer. The numerical results demonstrate that the additional harmonic substantially alters the flow field and temperature distribution near the surface. The induced velocity normal to the y axis can substantially thicken the boundary layer, implying that its growth is not due solely to the momentum and thermal diffusion normal to the y axis along a wavy surface.


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