THE LATTICE-BOLTZMANN MODEL FOR THE VISUAL SIMULATION OF SMOKE
Usman Alim · 2007
The modeling and simulation of smoke, like other fluid phenomena, is an important and challenging problem in Computer Graphics. In order to achieve high levels of visual realism, physically based methods are usually used. Smoke is treated as a non-reactive substance that is transported by an incompressible fluid. The dynamics of such a fluid is described by a set of non-linear partial differential equations known as the Navier-Stokes (NS) equations. Numerical methods for solving the NS equations can broadly be classified into two categories, top-down and bottom-up. Top-down methods are well-studied and have been successfully used in Computer Graphics to produce highly realistic animations of smoke and other fluid phenomena. On the other hand, bottom-up methods such as the LatticeBoltzmann Method (LBM) are still being improved and have only been recently investigated by the Computer Graphics community. In this thesis, we adapt the Lattice-Boltzmann Method for the purpose of smoke simulation in both two and three dimensions, and qualitatively compare the simulation results with those obtained through a top-down method. In order to achieve visual realism, we use physically based buoyancy and vorticity forces to drive the flow and employ a semiLagrangian method to advect smoke densities along the flow. Our simulation results reveal that the LBM retains much of the realism characteristic of the top-down methods, and at the same time, offers considerable advantages in terms of simplicity and efficiency.