On the Asymptotic Approach to Thermosolutal Convection in Heated Slow Reactive Boundary Layer Flows

Abstract

The study sought to investigate thermosolutal convection and stability of two dimensional disturbancesimposed on a heated boundary layer flow over a semi-infinite horizontal plate composed of achemical species using a self-consistent asymptotic method. The chemical species reacts as it diffusesinto the nearby fluid causing density stratification and inducing a buoyancy force. The existence ofsignificant temperature gradients near the plate surface results in additional buoyancy and decrease inviscosity. We derive the linear neutral results by analyzing asymptotically the multideck structure ofthe perturbed flow in the limit of large Reynolds numbers. The study shows that for small Damkohlernumbers, increasing buoyancy has a destabilizing effect on the upper branch Tollmien-Schlichting (TS)instability waves. Similarly, increasing the Damkohler numbers (which corresponds to increasing thereaction rate) has a destabilizing effect on the TS wave modes. However, for small Damkohler numbers,negative buoyancy stabilizes the boundary layer flow.