多相流动的光滑粒子流体动力学方法研究综述

A REVIEW OF SMOOTHED PARTICLE HYDRODYNAMICS FAMILY METHODS FOR MULTIPHASE FLOW

光滑粒子流体动力学(smoothed particle hydrodynamics,SPH)具有粒子方法的无网格和全拉格朗日特征,适用于具有界面大变形、不连续性和多物理场的多相流的高精度模拟.SPH方法模拟多相流已有大量报道,具体的实现方式也大不相同.本文首先阐述了采用SPH方法模拟流体的基本控制方程,以及求解过程中需要考虑的流体压力求解、表面张力、固体边界等问题.整理和总结了基于SPH方法进行多相流模拟的主要实现方式:(1)双流体模型的拉格朗日求解器:两相离散为两组独立SPH粒子,并用显式相间作用耦合两相;(2)多相SPH方法:SPH方法对多相流模拟的自然延伸,相间作用由SPH参数隐式描述;(3)SPH与其他离散方法的耦合:差异较大的两相各自采用不同离散方法,发挥不同拉格朗日方法的优点;(4)SPH和基于网格方法的耦合:网格方法处理简单的单相流动主体,获得精度和效率间的平衡.另外,还在模拟参数物理化等方面论述了与SPH方法模拟多相流相关的一些改进和修正方法,并在最后讨论和建议了提高多相流SPH模拟效率和精度的措施.

With meshfree and fully Lagrangian features of particle methods,smoothed particle hydrodynamics(SPH)is suitable to achieve high-accurate simulations of multiphase flows with large interfacial deformations,discontinuities,and multi-physics.Multiphase flow simulations with SPH methods have been reported abundantly and the specific implementations are much different.In this review,the basic SPH method and issues about fluid pressure,surface tension and solid boundary are discussed.And various implementations of SPH for multiphase flow simulation are mainly summarized as:(1)Lagrangian solver for the two-fluid model(TFM):The two phases are discreterized into two independent groups of SPH particles and coupled by the explicit interphase interaction;(2)multiphase SPH:The multiphase SPH method is considered as the natural extension of SPH method on multiphase flow simulation,and the interphase interaction is implicitly described by SPH parameters;(3)coupling of SPH and other discrete methods:The two phases with large differences each adopt different discrete methods to give play to the advantages of different Lagrangian methods;and(4)coupling of SPH and grid-based methods:The grid method handles the simple main-flow to obtain the balance between accuracy and efficiency.Also,some issues associated with SPH simulations of multiphase flows,such as the physicalization of simulation parameters and the improvement of accuracy and efficiency,are suggested as requiring attention.