Experimental Study of Force Balance and Interaction between Flow in the Main Channel and on the Floodplains in Skewed Compound Channel with Inclined Floodplains

In non-prismatic compound channels due to the mass and momentum exchange between the main channel and floodplains, the flow interaction between channel sub-sections is higher than prismatic compound channels. As a result, in this form of channels, the study of apparent shear forces create at the vertical interface between the main channel and floodplains are much more complex. In the present research, the velocity and boundary shear stress distributions were measured at different sections along the skew part of the flume. Also using the experimental data and the momentum equations the flow interaction between the main channel and floodplains have been investigated. Measurements have been performed for two skew angles of 11.31 and 3.81 degrees and three relative depths of 0.2, 0.3 and 0.4. Investigations indicate that the flow interaction between the main channel and the converging floodplain is generally greater than the flow interaction between the main channel and the diverging floodplain. Also, the side slope of the floodplains, has increased the amount of apparent shear force at the interface between the main channel and floodplains.