Influence of aeration and initial water thickness on axial velocity attenuation of jet flows

Abstract

With the development of ski-jump energy dissipation for high and large discharge among the hydraulic projects, the effects of characteristics of water flow on energy dissipation are increasingly important. In the present study, the effects of aeration and the initial water thickness on axial velocity attenuation of jet flow were analyzed, using variance analysis and numerical calculated methods. From the analysis of test data, both of the air concentration and initial water thickness are sensitive factors for the axial velocity attenuation of jet flow along the axial way, and there is no significant interaction effect between the aeration and initial water thickness. Aeration has a more significant effect on the axial velocity attenuation of jet flow. Decreasing the initial water thickness of jet flow can reduce the length of jet core, and make the initial position of axial velocity attenuation closer to the nozzle exit. The numerical calculation results show that aeration can contribute to the enhancement of entrainment ability of jet flow, which may improve the interaction between jet flow and surroundings. For ski-jump energy dissipation among the hydraulic projects, combining aeration with decreasing initial water thickness of jet flow is an effective way to enhance the rate of axial velocity attenuation. © 2013 Zhejiang University and Springer-Verlag Berlin Heidelberg.