基于Ansys的渗流自由面计算方法

对渗流自由面计算的单元传导矩阵调整法进行了改进。在局部坐标系下，将单元离散为一系列面元（三维为体元），根据面元或体元形心处的压力水头值来确定面元或体元的权系数，然后按加权平均确定单元的等效渗透系数，该方法既可以避免复合单元中自由面上下面积或体积的计算，面元或体元的离散密度也可以任意选择，简化了计算程序。通过预设的收敛参数来控制迭代过程，可避免相邻两次计算的渗透系数变化太大而难于收敛。以Ansys为开发平台，用APDL语言编写了相应的计算程序，扩展了Ansys的计算功能，为渗流自由面计算提供了新途径。算例表明：该方法的收敛性较好、计算精度较高，能满足工程需要。

Method for Seepage Analysis With Free Surface Based on Ansys

An improved element conductivity matrix regulative method for seepage analysis with free surface is proposed. The elements are discretized to a series of panels （cells for 3D） in local coordinate system, the weight coefficient of panel or cell is determined according to the pressure head in the center of it, then the equivalent permeability coefficient of element is obtained by weighted averaging, this method can avoid area or volume calculation near the free surface and the mesh density of panel or cell is optional, the program is simplified. The iterative process is controlled by setting convergence parameter in advance, avoiding convergent difficulty due to the enormous change of permeability coefficient between two successive iterations. Seepage analysis program is coded with APDL language of Ansys, the function of Ansys is extended and a newly approach for seepage analysis with free surface is presented. The numerical examples show that this improved method can meet engineering requirement for its better convergence and higher accuracy.