Boundary layers in free convection

The problem of free convection and mass transfer near a vertical wall is studied for the cases where the motion is described by the classical Oberbeck-Boussinesq model and the model of microconvection. In both cases, boundary layers are developed at high Schmidt numbers. Formulas for Nusselt (local and overall) numbers are obtained by solving the relevant problems for these layers. Initial asymptotic forms are also considered.