Imposing accurate wall boundary conditions in corrective‐matrix‐based moving particle semi‐implicit method for free surface flow
Imposing accurate wall boundary conditions in corrective‐matrix‐based moving particle semi‐implicit method for free surface flow
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DOI：
10.1002/fld.4878
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发表时间：
2020-08
影响因子：
1.8
通讯作者：
Guangtao Duan;T. Matsunaga;A. Yamaji;S. Koshizuka;M. Sakai
中科院分区：
文献类型：
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作者：
Guangtao Duan;T. Matsunaga;A. Yamaji;S. Koshizuka;M. Sakai
在移动粒子半隐式方法中，通过引入修正矩阵来恢复离散格式的一致性，可以显著提高内部粒子的计算精度。在这种情况下，由于自由表面和壁边界的误差成为主导。基于近年来对Neumann边界条件的研究（Matsunaga et al，CMAME，2020），将MPS中的校正矩阵格式推广到直接精确地施加Neumann边界条件。然而，由于不完整/有偏见的邻居支持引起的有偏见的误差，新方案仍然很容易引发自由表面的不稳定性。因此，现有的基于虚拟颗粒和保守梯度模型的稳定格式被应用到自由表面和附近的颗粒，以产生一个稳定的过渡层在自由表面。新的修正矩阵格式仅适用于稳定过渡层下的粒子，以改善壁面边界条件。三个自由表面流动的数值算例表明，所提出的方法可以帮助减少压力/速度波动，从而进一步提高精度。
Corrective matrix that is derived to restore consistency of discretization schemes can significantly enhance accuracy for the inside particles in the Moving Particle Semi‐implicit method. In this situation, the error due to free surface and wall boundaries becomes dominant. Based on the recent study on Neumann boundary condition (Matsunaga et al, CMAME, 2020), the corrective matrix schemes in MPS are generalized to straightforwardly and accurately impose Neumann boundary condition. However, the new schemes can still easily trigger instability at free surface because of the biased error caused by the incomplete/biased neighbor support. Therefore, the existing stable schemes based on virtual particles and conservative gradient models are applied to free surface and nearby particles to produce a stable transitional layer at free surface. The new corrective matrix schemes are only applied to the particles under the stable transitional layer for improving the wall boundary conditions. Three numerical examples of free surface flows demonstrate that the proposed method can help to reduce the pressure/velocity fluctuations and hence enhance accuracy further.