optimized free surface fluids on adaptive grids siggraph with … · 2011. 12. 30. · optimized...
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Optimized Free Surface Fluids on Adaptive Grids with the Lattice Boltzmann Method
Nils Thürey, Ulrich RüdeUniversity of Erlangen-Nürnberg, Computer Science 10 LSS, funded by DFG GRK-344
SIGGRAPH2005
Free Surface Fluids with the Lattice Boltzmann Method (LBM):
Optimizations with Adaptive Grids:
Unoptimized:(on average 69s / frame)
Optimized:(on average 24s / frame)
Unoptimized:(on average 76s / frame)
Optimized:(on average 37s / frame)
D2Q9 D3Q19
Stream DFsfrom adjacent Cells
Reconstruct DFs from Empty Celldirections
Reconstruct DFs from Direction ofInterface Normal
nn
Calculate Mass exchange with neighboringCells
mm
Perform Collisionas usual
The common LBM Models in 2D/3D:
CoarsenedInterface Regionwith 3 Grids
+ +
Grid G3, Coarse Grid G2 Grid G1FineActual Representation
on LBM Grid
Fluid Cell
Interface Cell
Coarse to Fine Grid Transfer
Fine to Coarse Grid Transfer
=
Time Stepping:
Step G3
t = 0
Step G2Step G1
t + 1
G2 > G1Step G1
G3 > G2
t + 2
Step G2
Step G1
G1 > G2
t + 3
G2 > G1Step G1
G1 > G2
t + 4
Step G3
Step G2
G2 > G3
Step G1
....
Lattice Boltzmann:- Similar to Cellular Automata - Regular Grid & discrete Velocites- Optimized Implementation possible
Free Surfaces:- Distuingish Empty, Fluid and
Interface Cells- Boundary Conditions and Surface
Tracking are handled at the Interface: