No abstract

In this work, a consistent Smoothed Particle Hydrodynamics (SPH) model is proposed to deal with interfacial multiphase uid ows simulation. A Continuum Stress Surface formulation (CSS) [1] was developed in the framework of SPH method using a non-conservative rst order consistency operator to calculate the divergence of stress surface tensor. This enables the enhancement of the stability near the uid interface. This formulation benets of all the advantages of the one proposed by Adami et al [2] and, in addition, it can be applied to more than two phases uid ow simulations. The generalized wall boundary conditions [3] are modied in order to be well adapted to multiphase uid ows with dierent density and viscosity. A particle redistribution strategy is proposed R1: as an extension of the damping technique presented in [3] to adequately initialize the conditions of gravitational multiphase uid ows. This strategy is based on the gradual application of a damping technique to mitigate gravity force in both momentum and pressure wall boundary condition equations. Several computational tests are investigated to show the accuracy and convergence of the proposed SPH interfacial multiphase model. Moreover, a simulation of a rising bubble crossing two stratied uid layers is performed with more challenging constraints such as high density ratio, high viscosity ratio, and with presence of triple points

This paper develops a consistent particle method for capturing the highly non-linear behavior of violent free-surface flows, based on an Enhanced Weakly Compressible Moving Particle Semi-implicit (EWC-MPS) method. It pays special attention to the evaluation and improvement of two particle regularization techniques, namely, pairwise particle collision (PC) and particle shifting (PS). To improve the effectiveness of PC in removing noisy pressure field, and volume conservation issue of PS, we propose and evaluate several enhancements to these techniques, including a novel dynamic PC technique, and a consistent PS algorithm with new boundary treatments and additional terms (in the continuity and momentum equations).Besides, we introduce modified higher-order and anti-symmetric operators for the diffusive and shear force terms. Evaluation of the proposed developments for violent free-surface flow benchmark cases (2D dambreak, 3D water sloshing, and 3D dam-break with an obstacle) confirms an accurate prediction of the flow evolution and rigid body impact, as well as long-term stability of the simulations. The dynamic PC reduces pressure noises with low energy dissipation, and the consistent PS conserves the volume even for extreme deformations. Comparing the role of these new particle regularization techniques demonstrates the effectiveness of both in assuring the uniformity of the particle distribution and pressure fields; nevertheless, the implementation of PS is found to be more complex and time-consuming, mainly due to its need for free surface detection and boundary treatment with many tuning parameters.