Theory of fully developed mixed convection including flow reversal: A nonlinear Boussinesq approximation approach

In this article, an exact solution is obtained to investigate the role of nonlinear Boussinesq approximation on mixed convection flow in a vertical channel subject to asymmetric wall heating. The nonlinear density variation with temperature (NDT) in the buoyancy term is introduced to the momentum equation and solved exactly by direct integration. During the course of graphical and numerical computations, results show that the role of NDT is to increase fluid velocity as well as skin‐friction while it reduces the rate of heat transfer. In addition, reverse flow formation at the walls is increased due to the inclusion of NDT (nonlinear Boussinesq approximation).