37. Flow Distribution in Diverging Compound Channel Using LES Models

During flood, water from the river inundates the floodplains causing mass destruction of human lives and properties. Thus, it is more essential to evaluate flow in the floodplains. The instant study is performed to understand the flow distribution in main channel and floodplains of a compound channel having symmetrical diverging floodplains due to difference in geometry and flow properties. Numerical experimentation is performed for diverging compound channel of different geometric and hydraulic conditions using ANSYS-fluent to study the effect of geometry and flow parameters on the flow distribution of such channels. Depth averaged velocity data obtained from the numerical experimentation for different sections have been taken to compute the discharge in that section for main channel and floodplain separately. Different numerical method like , LES model, k-model is utilized for the modeling test. Among these three models, LES models provided quite good agreement with the experimental data. Hence, by taking LES model, more different diverging channel configuration has been performed and the respective flow is simulated. Using the results of LES, more data sets are extracted and a model has been developed for the computation of the proportion of rate of flow in both main channel and flood plain for various relative flow depths and for different diverging angles. The applicability of the model is proved with the observational data sets of other researchers and found to provide less error in the subsection discharge computations of a non-prismatic compound channel. The reason for higher accuracy by LES prediction has been discussed and recommended for use in non-uniform open channel flow.