Compound wall treatment for complex turbulent flows

This work presents a generalised treatment of the wall boundary conditions for RANS computation of complex turbulent flows. The method blends two approaches: the integration to the wall (ItW) and the wall function (WF) approach, based on the unified velocity profile. Wall boundary condition can thus be applied irrespective of whether the wall-nearest grid point lies within the viscous sublayer, in the buffer zone, or in the fully turbulent region. This is a desirable feature for the flow simulations in complex domains where it is difficult to generate a computational grid that will satisfy a-priori either the ItW or WF prerequisites. The steady-state computations with fine and coarse meshes of the generic test cases (plane channel flow, backward-facing step and impinging jet) using the proposed compound wall treatment (CWT) are all in satisfactory agreement with the available experiments and DNS data.