Experimental Study on the Aerator's Air Hole Area, Cavity Length and Backwater in the Cavity

It cannot be ignored that the concrete surface of the discharge works may be seriously damaged caused by high speed flows. However, aerator installed at the bottom of spillway or tunnel is usually used to solve this problem in engineering. The function of the aeration facilities are influenced significantly by the cavity length and the backwater in the cavity, for the air holes will be blocked if there is a serious backwater in the cavity and so the aeration facilities will be ineffective. This thesis aims to study and analysis the relations among the air hole's area, the cavity length and the backwater depth in different conditions by the model experiments. The experiment results indicate that, the area of the air hole is a key factor to influence the jet cavity after the aerator. Aerator's body size and the chute slope affect cavity size and backwater in it greatly. For the chute with small bottom slope, more attention should be paid to the backwater in aerator's cavity.