A multi-phase particle shifting algorithm for SPH simulations of violent hydrodynamics with a large number of particles

Abstract

A numerical inconsistency has emerged for multi-phase smoothed particle hydrodynamics simulations when using very high resolution, made possible by graphical processing units. In violent flows unphysical voids and phase separation occur ultimately leading to numerical instability. New Fickian-based particle shifting algorithms with a selectively activated free-surface correction are developed for air-water simulations to prevent the creation of unnatural voids and maintain numerical stability through nearly uniform distributions. Using the shifting algorithm without surface correction in the air phase is recommended, with marginal improvements if the shifting algorithm is not applied in water. However, maintaining shifting in water would avoid possible void occurrence. The improvement is demonstrated using a dry-bed dam break and a sloshing tank case. A 3D case involving the impact of the water flow on an obstacle is compared with experimental data. The multi-phase SPH scheme gives closer agreement with experiment than a single-phase simulation.

A weakly compressible SPH method for violent multi-phase flows with high density ratio

“…Due to the highly non-linear phenomena in sloshing, this benchmark case has been used to validate many single-phase SPH methods (see e.g. [49,50,42]), as well as few two-phase counterparts [19]. In this section we consider a two-phase liquid sloshing case, which has been experimentally studied by Rafiee et al [49].…”

“…Such artifacts have also been observed in Gong et al [17]. To avoid unnatural voids in such simulations a regularization method based on particle shifting [18] was introduced [19]. A further improvement for simulating high Reynolds number flows is also proposed by applying a density diffusive terms [15] for smoother pressure and density fields [20].…”

Landslides and tsunamis predicted by incompressible smoothed particle hydrodynamics (SPH) with application to the 1958 Lituya Bay event and idealized experiment

“…Similar to Mokos et al [29], the normal-to-interface shifting is restricted for one of the two phases. This has been found to minimize any artificial numerical mixing of the two phases, caused by the shifting of different phase particles across the interface.…”

“…In many applications, the shifting methodology is found to be essential for both single-phase Newtonian and inelastic non-Newtonian applications as shown in Lind et al [20] and Xenakis et al [21], respectively, while it has recently proved to be beneficial in multi-phase SPH simulations (e.g. [29,30]). In this work, the compound shifting method [31] is used with…”

Free-Surface Flow Simulations with Smoothed Particle Hydrodynamics Method using High-Performance Computing

“…Since then, it has been used in several research areas, e.g. coastal engineering [3][4][5][6][7], flooding forecast [8][9][10][11], solid body transport [12][13][14][15], soil mechanics [16][17][18][19][20], sediment erosion or entrainment processes [21][22][23][24], fastmoving non-Newtonian flows [25][26][27][28][29][30][31][32][33], flows in porous media [34][35][36], solute transport [37][38][39], turbulent flows [40][41][42] and multiphase flows [43][44][45][46][47], not to mention manifold industrial applications (see, for instance [48][49][50]…”