Numerical aspects of including wall roughness effects in the SST k-ω eddy-viscosity turbulence model

This paper presents a study on the numerical requirements of including sand-grain wall roughness effects in the SST k-omega eddy-viscosity model. Three implementations are tried: two retain the direct application of the no-slip condition at the wall, the third is based on a wall function formulation. In the first two options the roughness effect is introduced via a change in wall boundary conditions, either for omega only or for k and omega. The two-dimensional flow along a finite flat plate is adopted to assess the numerical accuracy of the three approaches. The computed results are also compared with semi-empirical formula available in the open literature. It is demonstrated that sand-grain roughness effects can be simulated with acceptable numerical uncertainties with all three options, but the numerical settings to achieve that goal differ significantly. (c) 2010 Elsevier Ltd. All rights reserved.