Hydraulics simulation based on the two-phase SPH model

The two-phase flow of air and water is a common problem in the hydraulics simulation, which is difficult to track the deformations of interface with conventional numerical methods based on Eulerian grid-based approaches. As a Lagrangian mesh-less particle method, the Smooth Particle Hydrodynamics (SPH) model has a great advantage in modelling the interface flow. Due to the limitation of the single phase SPH model based on the platform of DualSPHysics, a two-phase SPH model is developed in the paper to investigate the mechanics of aerated flow with large density differences. However, the Mach number appears different in each phase, and the time step must be adjusted to the maximum velocity, which may result much more complexity. At the same time, the existence of interphase forces causes the interaction between different phases and increases energy loss subsequently. In order to improve the simulation precision and track a smoother interface, the SPH method developed in the paper is based on the two-phase weakly-compressible SPH (2P CMS) model with corrected momentum equations, which combines with the particle pair search method and separate neighbour particle lists method. To validate the new SPH model, the dam break experiment conducted by Zhou in 1999 is employed. The comparison shows that the corrected SPH model can track the deformations of interface in the two-phase flow easily. It demonstrates that the two-phase SPH model performs more accurately than the single phase SPH model.