【作者】 田会静；

【导师】 练继建；

【作者基本信息】 天津大学 ， 水利水电工程， 2007， 硕士

【摘要】 随着高坝的不断兴建,高速水流引起的脉动荷载对水工建筑物的影响也越来越成为工程上关注的焦点。由于水流脉动压力成因极其复杂,许多重要的数据都只能通过原型观测或是相应的水工模型实验来获得。但是模型实验也存在很多的不足之处,例如,实验过程中外界因素的干扰,模型比尺相似律问题等。因此迫切需要其它方法对水流脉动进行分析研究。水力学与计算机技术有机结合产生的CFD数值模拟技术极大地增强了解决复杂问题的能力。相比模型实验,数值模拟技术具有可实现对复杂流场在理想状态下的全域模拟,提供的信息量大而丰富,可直接对原型进行模拟而不用考虑相似律问题等优势。本文所要研究的主要内容就是采用大涡模拟方法对水跃现象中的水流脉动压力进行模拟,并通过模型实验进行验证。主要研究内容和成果有:(1)通过大涡模拟数值计算方法,利用VOF自由液面追踪方法,建立三维有限元数学模型,对带自由表面的水跃现象进行数值模拟。(2)进行水工模型实验,对脉动壁压实验结果进行统计分析,包括标准差、偏态系数、峰态系数、概率密度函数,脉动壁压的时空相关特征、功率谱密度函数等,并将计算结果与实验结果进行对比,两者吻合较好,表明大涡模型能成功地模拟出水跃现象中的水流脉动压力。(3)在此基础上,分析水槽侧壁上水流脉动压力沿水深的分布规律。(4)将大涡模拟方法应用到水利工程中,对青铜峡泄洪闸的流场和水流脉动压力进行模拟,表明采用大涡模拟方法对大尺度模型进行三维数值模拟是可行的。更多还原

【Abstract】 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.更多还原