基于格子玻尔兹曼法的三维溃坝流数值模拟与验证

Numerical simulation and validation of 3D dam-break flow based on Lattice Boltzmann Method

溃坝问题一直是验证数值模拟方法有效性的经典问题。利用基于格子玻尔兹曼离散方法研发的XFlow软件来模拟三维溃坝问题,以此验证其有效性并提出进一步的改进方向。为了对比前人所做的实验和模拟结果,计算了无障碍三维溃坝流相应监测点的压力、水位等要素,得到了水流演进过程,并提出了用增强固壁函数法处理固壁边界以增强计算的稳定性,另外还考虑了有矩形障碍物的三维溃坝问题。研究结果表明:该方法能捕捉到某一时间点的自由液面,相关数据计算结果准确,且无需划分网格,能减少工作量,但结果稳定性较差,合理运用边界处理方法能有效解决这一问题。

Dam-break flood simulation is a classical issue to verify the effectiveness of numerical simulation. In this paper,3 D dam-break flood is simulated and studied by XFlow software based on Lattice Boltzmann Method to verify its validity and find out improvement approach. In order to compare the results of previous experiments and simulations,the pressure,water level etc. at the corresponding monitoring points for barrier-free 3 D dam-break flow are calculated and the evolution process of the flooding is obtained. In the calculation,solid boundary is treated by Enhanced Solid wall to increase calculation stability. In addition,3 D dam-break flood discharge with rectangular obstacle is also considered. The research results show that the proposed method can capture the free liquid surface at a certain time point,the relevant calculation results are accurate and the work load is reduced because of meshing needless. However,the stability of the results is poor and the problem can be effectively solved by reasonably using the boundary treatment method.