EFFECT OF ANISOTROPY ON THE DEVELOPMENT OF CONVECTIVE BOUNDARY-LAYER FLOW IN POROUS-MEDIA

The effects of anisotropy on the development of thermal boundary layer flow in a rectangular porous cavity is studied. The side walls of the cavity are respectively heated and cooled isothermally. Top and botto m walls are insulated. The porous medium is anisotropic both in permea bility and thermal conductivity with its principal axes oriented in a direction that is oblique to the gravity vector. Scale analysis is app lied to predict the orders of magnitude involved in the boundary layer regime. In the large Rayleigh number limit, the governing boundary la yer equations are solved in closed form, using an integral approach. A finite difference method is used to obtain numerical solutions of the full governing equations. The effects of the anisotropy in permeabili ty and thermal conductivity on the development of free convective boun dary layer flow are found to be significant. (C) 1998 Elsevier Science Ltd