Experimental study on flow over rectangular Piano key weirs with slopped side crests

In this paper results of experiments on discharge coefficient of rectangular Piano key weirs are presented. Experiments were conducted using two Piano key weirs: one with sloped side walls crest and the other one with horizontal crest. Piano Key weirs with constant value of ratio of length to width were used. The results showed that water level upstream of weir with sloped side walls crest increased by about 11.02 percent. The discharge coefficient of weir with sloped side walls crest increased by about 4.8 percent. The efficiency of weir with sloped side wall crest is increases by about 7.3 percent. New equation for prediction of discharge coefficient of rectangular Piano key weir with sloped side walls crest and horizontal crest was obtained.