Stability of a suspension of gyrotactic microorganisms in superimposed fluid and porous layers

The aim of this paper is to investigate the stability of a suspension of motile gyrotactic microorganisms in a system that consists of superimposed fluid and porous layers. This is relevant to many biological applications, such as growing motile microorganisms in Petri dishes. By performing a linear stability analysis a correlation for the critical Rayleigh number is obtained.