An analytical method for over bank flow modeling

Abstract

The faster flowing main channel water and the slower flowing flood plain water induce a strong shear layer at the junction of a compound channel. Due to intense interaction at the junction between main channel and flood plain, the prediction of the flow parameters become complex particularly in shear layer regions. So, the current analysis presents an improved method to Reynolds averaged Navier–Stokes equation for predicting depth averaged velocity for a compound open channel. The new approximation includes the dispersion and transverse convection components in the secondary flow term of the governing equation. Independent calibrating coefficients are chosen for main channel, side slope, and flood plain regions. Further, an attempt has been taken to quantify the Reynolds shear stress term by introducing a new factor for shear layer regions of the compound channel. The approach is examined through the experimental data sets. For both homogenous and non-homogenous compound channels, the new approach is found to provide better results. Also for natural rivers, the improved method is tested and found to predict the flow variable with reasonable accuracy.