Assessment of Two Low-Reynolds-Number k-e Models in Turbulent Boundary Layers with Surface Roughness

The performance of two low-Reynolds-number k-e models developed for flows over rough walls is assessed by simulating the fully developed turbulent flows in rough circular pipes, in rough rectangular channels, and over rough flat plates. The computational results, including the log-law mean velocity, the skin friction coefficient, the roughness function, the turbulent kinetic energy, and the Reynolds shear stress, are presented. For the turbulent rough-pipe and rough-channel flows calculated, the results show various levels of agreement with measured data for both models. For the turbulent boundary layer, the results obtained by using one of the models agree satisfactorily with the measured log-law mean velocity profiles and roughness functions. Both models less satisfactorily predict the skin friction coefficient and the turbulent kinetic energy.