Effect of Intermediate Sill on the Performance of Stilling Basin Model

This research paper investigates about the performance of stilling basin models with different geometry of intermediate sill having height equivalent to the diameter of pipe outlet. The experimental study was carried out for three Froude numbers namely 3.85, 2.85 and 1.85 for non-circular pipe outlet. Performance index (PI) has been used to evaluate the performance of stilling basin models tested using same sand base material and test run time. The scour pattern was measured for each test run and flow pattern was also observed. After 15 tests runs, it was found that scour process were reduced for a specific geometry of intermediate sill having saquare shape of the height 1d at a particular location on stilling basin floor combined with end sill of particular size and shape. Performance of this model was found to be better than USBR VI impact basin for similar flow condition.