Prediction of Energy Loss in Compound Channels Having Enlarging Floodplains

Abstract

In this paper, energy loss in non-prismatic compound channels of different geometry and flow conditions are analysed. Two types of diverging compound channels are considered. Those are a) compound channel with diverging floodplain originating from compound channel with prismatic flood plain with angle 5.93 b) compound channel with diverging flood plain of 3.81, 5.7 and 11.3 angle originating from simple main channel. Due to non-uniformity of flow in such cases the prediction of flow parameters is much complex as compared to that in a prismatic compound channels. Investigators need an accurate value of energy slope for prediction of flow in such cases. Due to limited data sets available in literatures, application of CFD using ANSYS has been made to produce more datasets for non-prismatic compound channels. The results of discharges for different diverging angles are found to give satisfactory results when verified with the available experimental datasets. Energy slope of the non-prismatic compound channels are found to be function of non-dimensional geometric and hydraulic parameters like width ratio (), relative depth (), relative distance (Xr) and diverging angle () of the channel. An expression to predict the energy slope is developed which will be helpful for accurate prediction of flow in such cases. The model is verified well with present experimental channels and with the data of other researchers.