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运用快速畸变理论对河道中绕沙波流动进行了理论分析,重点探讨了无旋应变与持续切变效应对绕沙波流动波顶处湍流强度的影响,结果表明:在河道中绕沙波流动的外区,绕体前、后的水流湍流结构存在较大程度的关联,在用快速畸变理论研究绕沙波前、后湍动强度变化的过程中,必需同时考虑无旋应变与持续切变的影响.此外,还以长江下游扬中河段的太平洲为背景,采用水深平均模型及基于曲线网格的有限控制体积法对绕洲滩的河道二维非恒定流进行了数值模拟,并进一步就时变项采用隐式差分格式条件下时间步长选择对水位与流速计算成果的影响进行了分析.
Based on the theory of fast distortion, the influence of unsteady strain and continuous shear on the turbulence intensity at the top of the wave is analyzed. The results show that the flow around the sand wave , The turbulent structure of the water flow around the body before and after the body has a large degree of correlation. In the process of studying the turbulence intensity changes before and after the sand around by using the theory of fast distortion, it is necessary to consider both the non-rotational strain and the continuous shear On the background of the Taiping in the Yangzhong reach of the lower Yangtze River, a two-dimensional unsteady flow of the channel around the Qiantan beach was numerically simulated by using the water depth-averaged model and the finite control volume method based on curvilinear grid, The influence of time step selection on the calculation results of water level and velocity is analyzed under the condition of implicit difference scheme.