Free Surface Lattice-Boltzmann fluid simulations with and without level sets

We present two variants of free surface Lattice-Boltzmann fluid simulations for the animation of liquids in computer graphics. The Lattice-Boltzmann method is an attractive alternative to conventional fluid solvers, due to its simplicity and flexibility, especially for changing geometries and topologies. While our first method directly calculates the mass fluxes between the cells of the computational grid, another variant of the method is explained, that uses level sets to track the fluid surface. This has advantages for the smoothness of the fluid surface and improves the representation of details in the free surface, but makes the conservation of mass more difficult. Several examples will be shown to highlight the differences between the two methods.