Large Eddy Simulation And Experimental Study On Fluctuating Pressure Of The Hydraulic Jump

As a continual construction of high dams, the influence of fluctuating pressure caused by high speed discharge on hydraulic structure becomes the focus. Because the cause of fluctuating pressure is rather complex, many important parameters are obtained only from prototype observation or hydraulic model experiment. But there are many defects in model experiment, such as the influence of environment in the process of experiment, the similarity law of model scale. Therefore, other methods are needed urgently to study the pressure fluctuations.CFD numerical simulation technique which was combined organically by hydraulics and computer technology enhances the ability to solve more complex problems. In contrast with model experiment, numerical simulation technique has many advantages, as follows, the ability to simulate the whole region in perfect state, the information supplied greatly and abundantly, the ability to simulate prototype which don't need to consider the problem of similarity law.The main work of this paper is to simulate fluctuating pressure of the hydraulic jump by the method of large eddy numerical simulation and to proof the results by model experiment. The principal contents and achievements of the paper are as follows:(1) With large eddy numerical simulation, three-dimensional numerical model is established to simulate hydraulic jump with free surface by VOF free surface track method.(2) The statistical characteristics that consist of standard deviation, skewness, kurtosis, probability density function, space-time correlation and power spectral density function of the fluctuating pressure recorded in the experiments are analyzed in the paper. The numerical simulation results are analyzed and compared with the test results, and they are well agreed with each other. It shows that the large eddy numerical simulation can simulate the fluctuating pressure of the hydraulic jump successfully.(3) On the base, regularity of fluctuating pressure distribution on water channel's side wall is investigated in depth of water.(4) Applying the large eddy numerical simulation to hydraulic engineering, this paper simulates flow and fluctuating pressure of Qingtongxia sluice. The result shows that it is feasible to carry out three-dimensional simulation of large scale model with large eddy numerical simulation.