An Investigation of the Influence of Longitudinal Channel Slope on Secondary Currents in Compound Channels Using 2 D momentum Model



Secondary flow investigation could be regarded as an important issue in open channel flow, in spite of its lower quantity compared to the base flow in the water course. It should be given special consideration because of the influence on some hydraulic factors in open channel, specifically in compound channels. In compound channels' due to the difference in the flow velocity of the main channel and that of the floodplain, shear stress in inner layers of fluid increases which aid in developing secondary flow in the area. With regard to the nature of turbulent flow and shear stress, direct measurement of shear and secondary flow requires special laboratory instruments and techniques, while it has little practical importance. In this paper, by using simple available techniques, depth averaged flow characteristics were compiled and used along with two dimensional Shiono-Knight depth average model. The results indicated that the longitudinal slope does not affect the secondary flow and the eddy viscosity