Animation of Interacting Deformable Interfaces

This paper describes a Stokesian (slow viscous) flow simulation for producing accurate animations of interacting deformable interfaces separating two phases with different viscosities. This models several phenomena in their nativity, such as air bubbles rising in water, liquid metal drops coalescing, cell membranes interacting, soft docking of flexible molecules, etc. Starting from any initial configuration of "bubbles", and with gravity turned on, the bubble interfaces are continually evolved, as well as deformed based on the relative viscosities and the interfacial tension. The velocity computation and the interfacial dynamics are achieved via a Boundary Element formulation of the governing Stokesian flow equation, while the interface evolution and topology maintenance utilizes radial basis reconstructions and adaptive remeshing. Effects such as bubble coalescence, bubble break-up, and additional near bubble interactions, can be accurately simulated and visualized. These last three effects in particular require adaptive refinement of meshed geometry and controlled coupling of the numerical errors in computation to yield topologically realistic looking phenomena rendering.