A partitioned continuous surface stress model for multiphase smoothed particle hydrodynamics

A density partitioned continuous surface-stress (CSS) model is presented within a multi-phase smoothed particle hydrodynamics (SPH) framework. We follow the original work of Adami et al. (2010) [1] to partition the surface-tension force from a zeroth-order consistent continuum surface-stress model. As a consequence of the scaled surface-tension force, both the surface-tension based artificial speed of sound and the numerical time step criteria can be relaxed for phase interfaces with high density ratio. A new color-gradient treatment and a static contact angle based surface-stress boundary condition is introduced to incorporate wetting behavior. All models are validated by comparison to analytical solutions of several surface-tension dominated flows. The resulting scheme is demonstrated to handle both capillary and Marangoni forces for high density and viscosity ratios.