Two-phase SPH simulation of fluid–structure interactions

• Two-phase SPH model is used for various fluid–structure interaction problems.
• Modified solid boundary treatment is proposed to improve the model accuracy.
• Laboratory experiment is carried out for the wedge entry process.
• Comparisons are made between the single- and two-phase simulations.

In this paper, a two-phase Smoothed Particle Hydrodynamics (SPH) method is used to simulate the fluid–structure interactions with violent deformation of the free surface. An improved solid boundary treatment is proposed based on the accurate pressure interpolations of the inner fluid particles. The model performance is validated by sloshing in a water tank and dam break flow impact on a vertical wall. In the practical model applications, a two-dimensional wedge entry into the static water is studied, for which the flow fields of water and air phases are computed simultaneously. It has been found that both the water flow around the wedge cavity and the air flow inside are reasonably predicted. Also the two-phase model has been found to accurately provide the flow features throughout the entire entry process, while the single-phase model can only predict the flows before the closure of the cavity due to the lack of air modeling. Besides, a laboratory experiment on the wedge entry has also been carried out for the validation purposes.