Estimation in jet deflection angle of deflector on the chutes.

Ski jumps are commonly used to discharge flow away from release structures into downstream rivers for energy dissipation. However, due to large intersection angles of jet and river flow or the jet impacting position unreasonable, the serious sour of riverbed or bank may occur, threatening the security of hydraulic structure. Hence, the impacting position and direction of jet from ski jump are pressing for research. For obtaining a controllable and desired outflow condition, adding rectangular tetrahedral deflector is a common and effective measure to change the flow direction. In this study, physical experiments and numerical simulation were conducted and the effect of the deflector contraction ratio on the flow deflection angle was revealed. The results indicate that the contraction ratio is a key parameter of the deflector, and a larger contraction ratio contributes to a larger jet deflection angle. Based on the data in the present and previous studies, a new empirical expression for estimating the deflection angle is proposed for rectangular tetrahedral deflector. By contrast with previous research, the calculated result from the expression presents a better agreement with the test data. [ABSTRACT FROM AUTHOR]