Stability of Double-Diffusive Convection in a Porous Medium with Temperature-Dependent Viscosity: Brinkman–Forchheimer Model

In this article, the problem of double-diffusive convection in a porous layer when the viscosity depends on the temperature and using Brinkman–Forchheimer model has been introduced by using the linear and nonlinear energy theories. For linear theory, the critical Rayleigh numbers have been derived and then numerically calculated. However, for nonlinear theory, the critical threshold was derived in three different ways and the results were compared with the results of the linear analysis.