Stable Free Surface Flows with the Lattice Boltzmann Method on adaptively coarsened Grids
Nils Thürey, Ulrich Rüde
Abstract:
In this paper we will present an algorithm to perform free surface flow simulations
with the lattice Boltzmann method (LBM) on
adaptive grids. This reduces the required computational time by more than
a factor of three for simulations with large volumes of fluid.
To achieve this, the simulation
of large fluid regions is performed with coarser grid resolutions.
We have developed a set of rules to dynamically adapt the coarse regions to
the movement of the free surface, while ensuring the consistency of all grids.
Furthermore, the free surface treatment is combined with a Smagorinsky turbulence
model and a technique for adaptive time steps to ensure stable simulations.
The method is validated by comparing
the position of the free surface with an uncoarsened simulation.
It yields speedup factors of up to 3.85 for a simulation with
a resolution of 480^3 cells and three coarser grid levels, and thus
enables efficient and stable simulations of free surface
flows, e.g. for highly detailed physically based animations of fluids.
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