A Departure From the Darcy Model in Boundary Layer Natural Convection in a Vertical Porous Layer With Uniform Heat Flux From the Side

1985 ◽  
Vol 107 (3) ◽  
pp. 716-720 ◽  
Author(s):  
D. Poulikakos
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.


2006 ◽  
Vol 129 (6) ◽  
pp. 717-726 ◽  
Author(s):  
Kamil Kahveci

This numerical study looks at laminar natural convection in an enclosure divided by a partition with a finite thickness and conductivity. The enclosure is assumed to be heated using a uniform heat flux on a vertical wall, and cooled to a constant temperature on the opposite wall. The governing equations in the vorticity-stream function formulation are solved by employing a polynomial-based differential quadrature method. The results show that the presence of a vertical partition has a considerable effect on the circulation intensity, and therefore, the heat transfer characteristics across the enclosure. The average Nusselt number decreases with an increase of the distance between the hot wall and the partition. With a decrease in the thermal resistance of the partition, the average Nusselt number shows an increasing trend and a peak point is detected. If the thermal resistance of the partition further declines, the average Nusselt number begins to decrease asymptotically to a constant value. The partition thickness has little effect on the average Nusselt number.


Sign in / Sign up

Export Citation Format

Share Document