FLOW CAHACTERISTICS OF PLUNGE FLOWS IN WELL-MIXED AND STRATIFIED RESERVOIRS

Flow characteristics of plunge flows in well-mixed and stratified reservoirs are investigated experimentally. The study is directed towards the estimation of the densimetric Froude number Fp at the plunge point and the initial mixing rate γ. The internal critical slope Ic is found to be about 1/50. It is shown that the values of Fp in well-mixed reservoirs are strongly affected by the inflow densimetric Froude number Fo and the channel slope I when plunging takes place near the inlet of a reservoir, whereas Fp becomes a constant value of 0.5 in both mild and steep channels when these effects are less pronounced, and that for the range of I=1/150-1/30 is quantifed as a linear function of I. It is also found that the values of Fp in well-mixed reservoirs with a steep channel are also well approximated as 0.5 when Fo is more than about 2.0.