Abstract

Foaming bubbles are a common element seen throughout both nature and man-made civilization. All types of bubbles behave variably. For example, foams float in water, splash out from buckets, and are squeezed out of hand soap dispensers. Due to their complexity and variance in behavior, they can be expensive to simulate and difficult to portray realistically. When simulating dense concentrations of bubbles with little free-flowing water, such as soap films, three variables need to be accounted for: how the fluid will move, how the bubbles will be sized, and how the bubbles will behave when they come into contact with each other. We propose a novel dry foam simulation algorithm, Foam Fraction Flow, which combines methods from three simulation algorithms: weighted Voronoi diagrams, volume fractions for multiphase fluids, and the moving least squares material point method. Taking inspiration from soda simulation, Foam Fraction Flow leverages weighted Voronoi diagrams to give moving bubbles accurate shapes when they come into contact with each other. Additionally, bubble sizes are determined by volume fractions: ratios of liquid to gas at each point of the simulation. This is a technique used for simulating multiphase fluids. However, unlike previous volume fraction implementations, Foam Fraction Flow uses an MLS-MPM physics-based fluid solver based on the intrinsic physical properties of foam, with a multiphase mixture of foam and fluid particles, to drive the overall fluid motion. This solver is used to simulate bubble bath foam, soap film, and hot tub foam. Our experiment illustrates that low-density dry foams with varying levels of water can be efficiently and accurately simulated using this new method. The algorithm runs in the Unity game engine, from around 6 to 12 seconds per update, depending on the type of foam being simulated.

Degree

College and Department

Computational, Mathematical, and Physical Sciences; Computer Science

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