ENTROPY BASED ESTIMATION OF DISCHARGE IN LABORATORY FLUME

Abstract

Discharge or river runoff refers to the volume of flow passing through a cross-section at a given instance of time. River discharge estimation plays a pivotal role in studies related water resources assessment, understanding different hydrological processes, flood forecasting and planning a rational and responsible use of water resources, ensuring that they are correctly and adequately managed. For measurement of discharge at a river cross-section, area-velocity is the most commonly used method. In discharge estimation process, velocity distribution is of prime importance, for which various traditional methods like Prandtl-Von Karman logarithmic law and Power law are used. But these laws are valid only for wide channels, in which velocity varies in only in longitudinal direction with maximum velocity at free surface. Considering the limitations of the traditional methods, concept of entropy theory for estimation of cross sectional mean velocity was introduced in the field of hydraulics in mid of 20th century. Experimental investigations on laboratory flume have been conducted to collect precise data on discharge passing through a channel section and corresponding velocity distribution along several verticals with depth to apply the concepts of entropy theory for calculate the parameters which can be used to predict the discharge by simply knowing the maximum velocity across the section. Work was carried on Laboratory flume in the Watershed Laboratory of the Department of Hydrology, IIT Roorkee under controlled conditions. Discharge observations taken using conventional techniques have been simulated for same conditions using Entropic model and results were found to have good correlation with corresponding observations proving the applicability of this theory for quick and accurate discharge estimation.