Underwater bubbles and coupling.

We present an approach to simulating underwater bubbles. Our method is sparse in that it only simulates a thin band of water around the region of interest allowing us to achieve high resolutions in turbulent scenarios. We use a hybrid bubble representation consisting of two parts. The hero counterpart utilizes an incompressible two-phase Navier-Stokes solve on an Eulerian grid with air phase also represented via FLIP/APIC particles to facilitate volume conservation and accurate interface tracking. The diffuse counterpart captures sub-grid bubble motion not “seen” by the Eulerian grid. We represent those as particles and develop a novel scheme for coupling them with the bulk fluid. The coupling scheme is not limited to sub-grid bubbles and may be applied to other thin/porous objects such as sand, hair, and cloth.