Analysis of Kinetic Energy Loss Intensity in Compound Channels

The intense momentum transfer on the vertical interface between main channel and flood plain in a compound channel, makes its conveyance capacity decrease. To reflect the kinetic energy loss intensity in a compound channel, two new concepts, transverse kinetic energy correction coefficient (TKECC) and kinetic energy loss rate (KELR) are put forward for steady, mean and turbulent flow.Through the analysis of the mechanism of kinetic energy loss in compound channels, a conclusion is drawn that TKECC is larger than 1 and KELR is larger than 0 in compound channels.By analyzing the experimental data from Science and Engineering Research Council-flood Channel Facility (SERC-FCF), it is found that TKECC and KELR are both related to shapes of cross section. Kinetic energy loss becomes weaker with main channel side slope factor increasing and becomes stronger with the ratio of main channel and flood plain width increasing. Kinetic energy loss in a symmetric compound channel is stronger than that in an asymmetric one. For all the shapes of cross section, kinetic energy loss increases with the relative depth increasing. After it reaches the largest value, it decreases with the relative depth increasing, and the compound channel ultimately shows a characteristic of single channels.