We consider the combined effects of suction and transverse anisotropy on the instability of the uniform thickness boundary layer which is formed on an inclined heated surface in a porous medium. When the medium is isotropic, the stability characteristics are shown to be very similar to that of the inclined Darcy-Benard problem. In particular, longitudinal rolls are always preferred, and transverse rolls are always stable when the inclination of the surface is greater than approximately 31.9°. Transverse anisotropy has no effect on the identity of the preferred mode of convection whenever the anisotropy parameter, ξ, is less than unity. When ξ > 1, there always exists a range of surface inclinations where transverse rolls are preferred. A detailed set of numerical results are given showing how the critical Rayleigh number and wavenumber vary with both inclination and ξ. © 2002 Published by The Japan Society of Fluid Mechanics and Elsevier Science B.V. All rights reserved.
- Fluid dynamics
- Porous materials