ABSTRACT
Explanation of non-prismatic compound channels advances the knowledge in real field problems and assists in modeling the non-uniform flows. While theoretical derivations and numerical modeling for flow prediction equations are well investigated by previous researcher, they are found to be complex in applying. It is observed that less work has been devoted to apparent shear stress calculation at the interface of a non-prismatic compound channels. Distribution of boundary shear force in main channel and floodplain is also another challenging task in non-prismatic compound channel. Here, expressions to predict percentage boundary shear distribution in floodplain zone and apparent shear at interface are presented and their inherent relationships are discussed. However, there is a plane where the apparent shear is zero (is known as plane of zero shear) needs to be evaluated for determination of accurate flow through divided channel method. It is found that the zero interface planes vary cross section to cross section along the length of the non-prismatic channel. The importance of this zero interface plane is recognized for non-prismatic compound channels and its dependency on non-dimensional channel geometric and hydraulic parameters is analyzed. Moreover, the current approaches are also capable of evaluating the intensity of momentum transfer across different interfaces and locating the zero shear interfaces for prediction of discharge by area method of reasonable accuracy. The performances of the models are found to give better results for diverging experimental data sets of recent investigators as compared to previous models.
