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首次在较粗网格下成功地由N-S方程直接数值求解了高雷诺数过跌坎水流.跌坎水流是典型的由大涡控制的紊流运动,作为一种近似可忽略小涡影响,网格尺度易满足描述大涡特征分辨率的要求,从而可在较粗网格实现直接数值求解N-S方程获得紊流流场.文中采用基于剖开算子法的欧拉-拉格朗日相结合的有限单元方法,对雷诺数Re=44000的二维跌坎水流进行了数值模拟.用16669个节点组成的三角形网格离散流场,在个人电脑上仅用150min即完成全部计算,不但给出了流场的时均特征,而且给出了它的紊动瞬时特征.数值试验表明,主要计算成果和试验甚吻合,由N-S方程直接数值求解工程中高雷诺数复杂紊流问题将成为现实.
For the first time, the high Reynolds number water flow is directly and numerically solved by the NS equation for the first time under coarser grids. The flow of water is a typical turbulent motion controlled by large eddy, as an approximation negligible small eddy effect, The scale can easily meet the requirement of describing the resolution of large eddy feature, so that the direct numerical solution of Navier-Stokes equations can be obtained on a coarser grid to obtain the turbulent flow field.In this paper, the Euler-Lagrange combination based on the split operator method Finite element method is used to simulate the two-dimensional flow of water with Reynolds number Re = 44000. Using a triangular grid composed of 16,679 nodes to disperse the flow field, the calculation is completed in only 150 minutes on the personal computer, not only The transient characteristics of the turbulent flow field are also given.Numerical tests show that the main computational results are in good agreement with the experimental results and the direct numerical solution of the Navier-Stokes equations to the high Reynolds number complex turbulence problems will become a reality.