Experimental investigation of selective withdrawal from a two layer fluid body

Abstract

Selective withdrawal from stable stratified fluid system is a well known technique of water quality management. Stratification is caused due to density variation in an incompressible fluid or entropy variation in compressible fluid. The causes of density variation are primarily temperature variation with depth and secondarily, by a variable concentration of dissolved or suspended solid. Selective withdrawal is one, where one can select the strata of the fluid at the sink level. Hence, the !low is restricted into horizontal layer which enables the water to he withdrawn in horizontal layers. Flow from stratified fluid system depends on many parameters like nature of stratification, thickness of interface, flow-rate, shape of sink, location of sink, rotation etc. l3ut for characterizing the flow, the above physical parameters are converted into fluid dynamic parameters as drawdown, Froude numbers (densimetric Froude number, interface Froude numher and intake Froude number) etc. In the present thesis, sinks were taken capped and observed that cap size on sink effects percentage of drawdown significantly. Hence, it is also found that a generalized relationship hetwcen drawdown, Froude numbers and cap dimension parameter from observed data can be made.