TRANSVERSE MOMENTUM EXCHANGE IN COMPOUND CHANNEL FLOWS

摘要

The physical processes playing a role in the mixing zone on the interface between the channel and the floodplain of a uniform compound channel are studied in this paper. The transverse profiles of the mean streamwise velocity and the transverse shear stress in the mixing region are modeled by using an effective eddy viscosity. The newly developed eddy viscosity model contains (1) the effects of horizontal coherent structures moving on an uneven bottom taking into account the compressing and stretching of parts of the horizontal coherent structures and (2) the effects of the three-dimensional bottom turbulence. The so-obtained physically based model proved to be well capable of predicting the transverse profiles of the streamwise velocity, the transverse shear stress and eddy viscosity of the experiments in the Flood Channel Facility.