Incompressible-compressible flows with a transient discontinuous interface using smoothed particle hydrodynamics (SPH)
Incompressible-compressible flows with a transient discontinuous interface using smoothed particle hydrodynamics (SPH)
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DOI：
10.1016/j.jcp.2015.12.005
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发表时间：
2016-03
期刊：
影响因子：
--
通讯作者：
S. Lind;P. Stansby;B. Rogers
中科院分区：
文献类型：
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作者：
S. Lind;P. Stansby;B. Rogers
发展了一种新的两相不可压缩-可压缩光滑粒子流体动力学（SPH）方法，其中界面密度不连续。这适用于具有大密度差的水-空气问题。不可压缩相需要来自可压缩相的表面压力，并且可压缩相需要来自不可压缩相的表面速度。可压缩SPH用于空气相（低马赫数时采用等温硬化理想气体状态方程），无发散（基于投影）不可压缩SPH用于水相，并添加Fickian位移以产生足够均匀的颗粒分布，从而实现稳定、准确、收敛的解，而在压力场中没有噪声。移位是一个纯粹的数值粒子正则化装置。界面在高密度比下保持真实的材料不连续性，界面处具有连续的压力和速度。这种方法与物理的可压缩性和不可压缩性的代表是新的SPH和验证对半解析结果的两相拉伸和振荡水滴，低振幅无粘驻波的分析结果，Kelvin-Helmholtz不稳定性，和溃坝问题与高界面变形和影响的垂直墙的实验和其他数值结果是可用的。
A new two-phase incompressible–compressible Smoothed Particle Hydrodynamics (SPH) method has been developed where the interface is discontinuous in density. This is applied to water–air problems with a large density difference. The incompressible phase requires surface pressure from the compressible phase and the compressible phase requires surface velocity from the incompressible phase. Compressible SPH is used for the air phase (with the isothermal stiffened ideal gas equation of state for low Mach numbers) and divergence-free (projection based) incompressible SPH is used for the water phase, with the addition of Fickian shifting to produce sufficiently homogeneous particle distributions to enable stable, accurate, converged solutions without noise in the pressure field. Shifting is a purely numerical particle regularisation device. The interface remains a true material discontinuity at a high density ratio with continuous pressure and velocity at the interface. This approach with the physics of compressibility and incompressibility represented is novel within SPH and is validated against semi-analytical results for a two-phase elongating and oscillating water drop, analytical results for low amplitude inviscid standing waves, the Kelvin–Helmholtz instability, and a dam break problem with high interface distortion and impact on a vertical wall where experimental and other numerical results are available.