ON CHOICE OF TURBULENCE MODEL FOR PREDICTION OF FLOWS OVER RIVER BED FORMS

A fully developed turbulent open channel flow with a bed consisting of a space-periodic array of triangular elements has been numerically si mulated. The solution procedure is based on the pressure-correction fi nite volume method with a collocated variable arrangement. Decoupling of the equations, inherent to the collocated variable arrangement, is avoided by using well-known Rhie and Chow interpolation technique. Rey nolds stresses are approximated using k-epsilon and a full transport R eynolds-stress models of turbulence. Wall boundary condition takes int o account wall roughness while the free surface is treated as a symmet ry plane for all variables apart from the dissipation of turbulence ki netic energy. Comparisons between prediction and the measurements indi cate that the k-epsilon model of turbulence is capable of predicting t he main features of the flow to the acceptable level of accuracy.