A lattice boltzmann method for fast and accurate fluid simulation

Abstract

Fluids such as gases, fires, rains, and waters are essential parts for real-world scenes surrounding us. For the last two decades, visual fluid simulation has drawn great attentions in computer graphics. Well-developed techniques in computational fluid dynamics(CFD) have been adapted to creation of visual effects for feature films, television programs, and video games. Physically-based fluid animation is typically done by numerically solving the Navier-Stokes equations. In addition, a level set method is adopted to capture the time-varying interface between water and air. In the thesis, we introduce an approach to fluid simulation, by combining existing techniques. We address three issues: computational efficiency, interface capturing, and image synthesis. For computational efficiency, an LBM~(lattice Boltzmann method) is adopted as a numerical scheme for solving the Navier-Stokes equations. We adopt a stable LBM which can be applied to fluids of low viscosity. We also employ a unified method to handle a variety of boundary conditions. A diffuse-interface method is introduced to accurately capture the interface between multiphase flows. Unlike conventional level set methods, our method does not require a reinitialization process. Moreover, no fictitious particles are necessary for volume conservation. Given a still picture, TIP~(tour into the picture) generates a walk-through animation of a 3D scene reconstructed from the picture. We deal with water surface reflection while allowing foreground objects to move. Provided with a set of points on background objects and their corresponding points on the water surface, a non-linear optimization problem is solved for the 3D scene parameters with respect to the camera position, to automatically construct a reasonable 3D scene model. To synthesize a stream of reflected images on the water surface in accordance with the camera movement, we propose a novel image-based approach, which makes the best of the lim...