Flow resistance in seepage-affected alluvial channel

Abstract

The problem of predicting flow resistance in the seepage-affected alluvial channels with satisfactory performance is of excessive attention to river engineers. Flume experiments were carried out in non-uniform sand bed channel for no seepage and seepage runs. Measures of turbulent parameters such as velocity and Reynolds shear stresses were found increasing with seepage which leads to increase in flow resistance with seepage. In this study, a flow resistance equation has been proposed empirically for the seepage affected alluvial channel. An empirical model of the flow resistance is proposed considering seepage as an explicit variable. The benefit of propose equation is that it introduces the influence of flow Reynolds number, friction Reynolds number, and seepage Reynolds number on flow resistance. The flow Reynolds number is directly proportional to the flow resistance while the friction Reynolds number and the seepage Reynolds number varied inversely with the flow resistance. The developed model predicts well the flow resistance in the seepage affected alluvial channel. The experimental data are also being used to evaluate the accuracy of existing flow resistance equations and has been found that none of the existing equations perform well for seepage-affected alluvial channel.