Physically-based Bubble Simulation

Among the most gorgeous natural scenes, close-up scenes of fluid phenomena attract most of the photographers, movie makers and game developers'eyes because of their extremely complicated surface turbulence and vivid visual effect.In off-line rendering do-main, a lot of movies are using more and more visual effects of fluid simulation(such as the movie "Poseidon"). And in real-time computer graphics, various kinds of com-puter games are also adding fluid simulation into game playing scenes (such as the game "Cryostasis"). As people's higher and higher requirements on movies and games'visual effects, physically-based methods are now becoming the most widely used techniques in both the industrial domain and the academic world. In the recent 20 years, researchers have made great efforts on a lot of splendid achievements, and these achievements have been widely used in industry. In fluid simulation, multi-phase fluid interaction including the bubble dynamics is a very important researching area.In this paper, we first give an up-to-date survey on the cutting-edge physically based bubble simulation techniques. We introduce three popular methods of simulating flu-ids,following with the comparison of bubble simulations based on three different method. The deformation under water of big bubbles is as important to bubble dynamics as the motion of bubbles. We introduce the evolving process of deformation simulation tech-niques in computer graphics, following with a discussion of the difference among several popular simulating methods.Then we present a real-time bubble simulation framework based on shallow water simulation(SWS), spherical vortex and boundary element method(BEM). We first solve the shallow water equations to simulate the water volume and the free surface. We then adopt the flow field of spherical vortices to affect the bubbles' motion and interaction. BEM is later used to simulate the bubbles'deformation when they rise in water. In addition, we propose a method to simulate the splitting and merging of bubbles, as well as illustrating how to handle deformable objects of different scales. We render bubbles and the fluid based on Microsoft DirectX efficiently with startling visual effect. As the algorithm we presenting here has high parallelism, we give a GPU implementation of the algorithm based on NVIDIA CUDA. We finally report extensive results generated on a standard PC to demonstrate the algorithm's realism and performance.The main contribution of this paper lies in:(1) Coupling shallow water and spherical vortices based bubble simulation with bound-ary element method to efficiently simulate underwater bubble's motion and defor-mation;(2) Demonstrating a simple method to simulate the splitting and merging of the bubbles underwater and handle deformable objects of different scales;(3) Presenting the GPU implementation of the algorithm based on CUDA.