丁坝绕流及局部冲刷坑二维数值模拟

针对以往常用的丁坝绕流流场计算方法存在的不足，建立了边界拟和曲线坐标变换下的平面二维变水深流函数-涡量数值模型。给出的坐标变换可用于三维；计算紊动扩散系数采用F分布，模型可用于变水深情况。用本文的模型，研究了单个丁坝与不同个数、不同形式的丁坝群产生的流速场与涡量场，给出涡量与局部冲刷坑范围及最大冲深部位。结果表明：计算得出的流函数、涡量、流速合乎规律；丁坝坝头处涡量较大，是形成冲坑的主要原因。方法较通常紊流模型及原参数解简便，为丁坝绕流及局部冲刷坑的数值模拟，开辟了一条新途径。

Two-dimensional Numerical Simulation on Spur Dike Circumfluence and Local Scour Hole

In view of shortcomings on the computation of spur dike circumfluence formerly,the two dimensional plane changeable depth stream function-eddy model in the boundary-fitted curvilinear coordinate was developed in this paper. The boundary-fitted curvilinear coordinate given can be applied in three dimensional problems.Turbulent diffusion coefficient was computed by F-distribution. The model can be used to changeable depth. The flow velocity field and eddy field of single spur dike and different number, different form spur dike group have been studied by the model and the eddy, whirlpool zone, maximum-depth position and change range of local scour hole have been given. The results shows that stream function, eddy, flow velocity computed are in line with law and the eddy at spur dike head is large which is the main reason of formation of scour hole. The method in this paper is simpler than velocity-pressure method of turbulent flow model. This paper develops a new method for numerical simulation on spur dike circumfluence and local scour hole.