SPH方法的运动边界条件研究Research on the moving boundary condition in SPH method

提出一种设置运动边界条件的方法，研究边界附近流体粒子积分截断和非物理穿透边界的问题。边界外的虚粒子在每个时间步由边界附近流体粒子对称生成，赋予相应的物理量，并在虚粒子中引入排斥力，利用拉格朗日形式的N‐S方程自编SPH程序，参考一维激波管的精确解验证边界方法的适用性，研究运动边界条件在计算模型中应用。激波管的模拟结果与精确解基本一致，且在运动边界模型中也计算获得合理的结果。文中提出的运动边界条件，避免了边界附近流体粒子积分截断问题，阻止流体粒子在边界处发生非物理穿透的现象。

Research on the moving boundary condition in SPH method

In order to study the integral truncation and unphysical penetration on fluid particles,a method of setting moving boundary condition was proposed.During every time step,ghost particles outside the boundaries were generated symmetrically by fluid particles and were given the corresponding physical quantities,in consideration of repulsive force in the ghost particles.By self-compiled SPH program that based on the N-S equation of the Lagrange form,using one-dimensional shock tube to exactly verify boundary conditions,finally to study how the moving boundary conditions were applied in the calculation model.Simulation results of shock tube were basically in line with the exact solutions,and reasonable results also were calculated in moving boundary model.Moving boundary condition was proposed in the paper to avoid the problem of fluid particles integral truncation near the border,and prevent unphysical penetration phenomenon.