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Understanding the flow characteristics of rivers in both their inbank and overbank flow conditions is an important task for engineers. So far, many studies have been carried out in compound channels with prismatic and non-prismatic floodplains. However, we still don't understand the effect of the floodplain's side slope on the flow field in compound channels. This paper presents the results of experiments on compound channels with skewed and inclined floodplains (lateral slope of 0.075). Velocity and boundary shear stress were measured at various experimental sections for different relative depths and two skew angles of 3.81º and 11.31º. Using the measured data, the secondary currents pattern, the apparent shear forces at the vertical interface between the main channel and floodplains, and the discharge distribution in the main channel and the floodplains along the flume have been investigated. The results of the experiments were then compared to the experimental data of the skewed compound channel with flat floodplains. The research shows that due to lateral flow and momentum exchange between flume subsections, the flow velocity, bed shear stress, and percentage discharge on the diverging floodplain are greater than those on the converging floodplain with the same cross-sectional geometry. [ABSTRACT FROM AUTHOR]

In this paper, the authors present experimental results of overbank flow in compound channels with nonprismatic floodplains and different convergence angles. The depth-averaged velocity, the local velocity distributions, and the boundary shear stress distributions were measured along the converging flume portion for different relative depths. The momentum balance is used to analyze the force acting on the flow in the main channel and for the whole cross section. Using the experimental data, various terms in the momentum equation are also calculated. The apparent shear forces on the vertical interface between the main channel and floodplains are evaluated for compound channels with nonprismatic floodplains, and the results are then compared with the prismatic cases. The energy balance in nonprismatic compound channels is also investigated by using the water surface elevation. [ABSTRACT FROM AUTHOR]