crash course in fluid simulations; basics and different practical approaches (particle-based, voxel-based, mesh-based)

1. Fluid Simulation
1.
2.
3.
4.
Computational Fluid Dynamics
Particle-based hydrodynamics
Voxel-based hydrodynamics
Mesh-based hydrodynamics

2. Computational Fluid Dynamics
• simulate the advection/motion of water
• Necessary:
– starting condition (water levels/distribution)
– starting momentum
• Conservation of Momentum:
m1u1  m2u2  m1v1  m2u2

3. Particle-based hydrodynamics
• approximation: water consists of particles
• initial momentum associated to some
particles
• compute particle interaction (momentum
transfer) on contact with neighbourhood
• conservation of momentum as driving force
• good method to compute contact with objects
(different materials)

4. Particle-based hydrodynamics
Real-time fluid simulation with adaptive SPH, Yan, H. et al.,
CASA 2009, Volume 20, Issue 2-3, pp. 417-426, June 2009

5. Voxel-based hydrodynamics
• water levels represented in volume image
• momentum given in vector image
• conservation of momentum via finite
difference
• memory-heavy representation
• easy to speed up on current hardware
architectures
• for real-world examples infeasible

6. Voxel-based hydrodynamics
GPU Gems 3 "Real-Time Simulation and Rendering of 3D Fluids"

7. Mesh-based hydrodynamics
• water is stored as 3D mesh with mass and
momentum attributes
• conservation of mass and momentum via FEA
• drawbacks:
– accurate volume mesh generation necessary
– slow runtime
• advantage: highly accurate (depending on the
mesh)

8. Mesh-based hydrodynamics