EXPERIMENTS WITH TRIANGULAR INTERMEDIATE SILLS ON STILLING BASIN MODELS

Sills play an important role in the design of stilling basin models used in reducing the excess energy downstream of hydraulic structure like over flow spillway, sluices, pipe outlets, etc. The effect of sill on the flow and or scour characteristics depends upon the configuration of the sill, its geometry and the flow regime. This research paper describes about the performance of stilling basin models for non circular pipe outlet using different size of triangular intermediate sill along with impact wall and end sill. The experimental study was carried out for three Froude numbers namely 3.85, 2.85 and 1.85 for non circular pipe outlet. Performance of stilling basin models has been evaluated by using Scour Index (SI) having same sand base material and test run time of one hour. The scour pattern was measured for each test run and flow pattern was also observed. After tests runs, it was found that scour process were reduced for a particular height and width of intermediate sill combined with impact wall and sloping end sill.