Single-Phase Trapped Air Simulation in Water Flow

Abstract

We introduce a novel practical single-phase particle simulation for trapped air bubbles in a turbulent water flow. Our model for a trapped air bubble is a low-density rigid body with a spherical shape, and our bubble interacts with water and other rigid bodies in a fully two-way manner. Our bubble is created at a trapped air pocket computed from the water volume. Stable and realistic bubble interactions are achieved using an impulse-based boundary force with non-positive coefficients of restitution. Subgrid-scale bubbles are also created to add more details using precomputed bubble data and an oscillating bubble mesh is used in rendering stage instead of a spherical shape for a soft look of the bubble surface. Our method can be easily implemented by extending an existing rigid body interaction of fluid solver, and it is fast compared to two-phase simulation because we do not simulate the air part.