The aim of this paper is to investigate the unstable nature of pressure computation focusing on incompressible flow modeling through the projection-based particle methods. A new approach from the original viewpoint of the momentum conservation regarding particle-level collisions, hereinafter refered to as time-scale correction of particle-level impulses (TCPI), is proposed to derive new source terms of pressure Poisson equation (PPE). This results in more stable computations with drastic reduction of unphysical pressure oscillations and more robust simulation with pressure magnitudes almost independent to time step. Moreover, compared to other strategies, no additional computational effort is required, its implementation is extremely simple, and the only numerical parameter is the propagation speed of the perturbations, of which the calibration is much more straightforward due to its physical meaning. Simulations were carried out using moving particle semi-implicit (MPS) method improved by the proposed approach. The comparisons of computed results with theoretical and experimental ones confirmed the effectiveness of the proposed approach.

本文的目的是通过基于投影的粒子方法研究压力计算的不稳定性质，重点是不可压缩流动建模。提出了一种从粒子级碰撞动量守恒的原始观点出发的新方法，以下称为粒子级脉冲的时间尺度校正 (TCPI)，用于推导压力泊松方程 (PPE) 的新源项。这导致更稳定的计算，显着减少非物理压力振荡，以及更稳健的模拟，压力幅度几乎与时间步长无关。而且，与其他策略相比，不需要额外的计算量，其实现极其简单，唯一的数值参数是扰动的传播速度，其中校准由于其物理意义而更加直接。使用由所提出的方法改进的移动粒子半隐式（MPS）方法进行模拟。计算结果与理论和实验结果的比较证实了所提出方法的有效性。