STUDY ON THE INFLUENCE OF BED ROUGHNESS ON ENTROPY PARAMETER

Abstract

In hydraulic engineering, flow resistance coefficient (Manning roughness coefficient) is one of the important parameters. It helps in flow forecasting in the channel, designing of hydraulic structures, the calculation of the distribution of velocities and sediment transport. So, the entropy velocity distribution requires the assessment of one parameter, M and this suggests to investigate the dependence of the entropy parameter on the hydraulic and geometric characteristics of the river cross section (Moramarco and Singh (2010)). Such studies, derived from the entropy velocity theory, proposed the formulation of the Manning’s roughness, n, based on Ф(M) and the positions in which the velocity is hypothetically zero, y0, and maximum, ymax, respectively. Experimental investigations on laboratory flume have been conducted to collect precise data on different discharges and at different bed roughness through a channel section and corresponding velocity distribution along several verticals with depth to apply the concept of entropy theory for calculating the entropy parameter which can be used to estimate the manning’s roughness. Work was carried out on Laboratory flume in the Watershed Laboratory of the Department of Hydrology, IIT Roorkee under controlled conditions. Roughness coefficient taken using conventional techniques, have been simulated for same conditions using Entropy model proposed by Tommaso Moramarco and V. P. Singh (2010). The results were found to have in good correlation with corresponding observations which validates the formulation relating Manning’s roughness to Entropy parameter