Investigation of Kinetic and Momentum Correction Coefficients and Flow Rate Estimation in Compound Channels

Non uniform flow Transverse velocity distribution in the main channel’s interface zone with floodplain in compound channels cause uncertainty to estimate in following parameters: the water surface profile, flood routing and sediment and pollution transport. The correction coefficients, (α) and (ß) were used respectively, to employ the impact of this uniformity on the kinetic energy and momentum values. In this study, via FCF data for compound channels, the influence of floodplain width (4.1, 2.25 and 0.75 m) on α and ß coefficient was investigated in symmetric and asymmetric compound channels. According to the results, the maximum value of α and ß was increased, due to increasing the width of the floodplain. Finally, the flow discharge was determined, with α and ß calculating values via CES software. Afterward, these values were compared with FCF laboratory data. The normalized root mean square error (NRMSE) was estimated in appropriate range, it equal to %15.6. This investigation showed that the high performance of the CES in determining the hydraulic parameters of flow such as discharge, in symmetric and asymmetric compound channels. But in general, this software overestimated the value of discharge.