Assessment of wall models for coarse-mesh RANS simulations

• Wall models were assessed within the context of coarse-mesh CFD simulations for engineering applications. • Coarse-mesh wall functions for the main turbulent quantities were implemented in OpenFOAM. • The analyzed extensions and corrections produce a better balance between accuracy and computational speed for coarse discretization, compared to traditional wall treatments. In the present article, the applicability and accuracy of different boundary conditions for the simulation of turbulent, single-phase flows with heat transfer were assessed within the context of coarse-mesh CFD simulations for engineering applications. Standard wall functions for relevant turbulent quantities were extended to include geometry-dependent effects and implemented as boundary conditions for existing OpenFOAM solvers, along with a set of coarse-mesh wall models based on empirical correlations. The different models were tested in the simulation of numerical experiments where high-fidelity simulations can be provided and, in general, results show that the application of the new set of boundary conditions produces a satisfactory prediction of the streamwise velocity and temperature in the evaluated conditions, even when the first cell center is far from the wall. The analyzed extensions and corrections produce a better balance between accuracy and computational speed for coarse discretization, compared to traditional wall treatments.