A physically consistent particle method for incompressible fluid flow calculation
A physically consistent particle method for incompressible fluid flow calculation
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DOI：
10.1007/s40571-020-00313-w
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发表时间：
2020-01
影响因子：
3.3
通讯作者：
M. Kondo
中科院分区：
文献类型：
--
作者：
M. Kondo
一般来说，在由保守力和耗散力构成的物理一致系统中，机械能单调递减。此功能对于设计粒子方法非常重要，粒子方法是用粒子近似连续介质流体的离散系统。当离散系统能够适应分析力学的框架时，它将是一个物理一致的系统，可以防止粒子散射等不稳定性以及非物理机械能的增加。在不可压缩粒子方法中也是这种情况。然而，大多数不可压缩粒子方法不满足物理一致性，并且需要经验松弛来抑制非物理能量行为导致的系统不稳定性。在这项研究中，开发了一种具有物理一致性的新的不可压缩粒子方法，即移动粒子完全隐式（MPFI）方法，其中离散相互作用力与耗散系统的分析力学框架相关。此外，为该系统提出了一种基于维里定理的新压力评估技术。使用MPFI方法，进行静压、液滴延伸、驻波和溃坝计算。提出了预测不可压缩自由表面流的压力和运动的能力，并通过计算研究了能量耗散特性随颗粒尺寸和时间步长的变化。
In general, mechanical energy monotonically decreases in a physically consistent system, constructed with conservative force and dissipative force. This feature is important in designing a particle method, which is a discrete system approximating continuum fluid with particles. When the discretized system can be fit into a framework of analytical mechanics, it will be a physically consistent system which prevents instability like particle scattering along with unphysical mechanical energy increase. This is the case also in incompressible particle methods. However, most incompressible particle methods do not satisfy the physical consistency, and they need empirical relaxations to suppress the system instability due to the unphysical energy behavior. In this study, a new incompressible particle method with the physical consistency, moving particle full-implicit (MPFI) method, is developed, where the discretized interaction forces are related to an analytical mechanical framework for the systems with dissipation. Moreover, a new pressure evaluation technique based on the virial theorem is proposed for the system. Using the MPFI method, static pressure, droplet extension, standing wave and dam break calculations were conducted. The capability to predict pressure and motion of incompressible free surface flow was presented, and energy dissipation property depending on the particle size and time step width was studied through the calculations.