Direct Numerical Simulation of Convective Channel Flow with Temperature and Concentration Gradients

Mixed convection in a differentially heated channel with an additional concentration gradient is investigated via direct numerical simulation (DNS) using a finite volume method based on fourth order accurate central differences in space and an explicit time integration scheme. The fluid is treated as a homogeneous fluid characterized by its temperature and mixing ratio. The Boussinesq approximation is employed to calculate the influence of the buoyant force resulting from density differences due to both quantities in preparation of future investigations of humid air flows in various ventilation applications. The simulations at different values for the modified Grashof number show a distinct effect of the mixing ratio on the flow and temperature profiles for values approximating the conditions found in humid air, in line with those found for purely thermal systems with comparable Grashof number.