Effect of Spillway Materials in Air-Water Interactions

The spillway system allows stabilization of the water free level and avoids variation in free level of water along the flow passage as a function of flow rate. The main problem in the spillway is the profiling of weir crest. The criteria that need to be satisfied are there should be no flow separation from the crest and there should be uniform circumferential flow to avoid flow asymmetry in the flow passage. Separation of flow leads to large impact velocity of the falling water, which would lead to the large-scale entrainment of air in water. This paper describes the effect of spillway materials by coating over the weir and changing the profile on air entrainment characteristics in the downstream.