Practical Course SC & VFree Boundary Value Problems

Dr. Miriam Mehl

Institut fürInformatik

Scientific Computingin Computer Science

Examples

Domain Representation

• imaginary fluid particles

fluid cell: #particles ≥ 1

empty cell: #particles = 0

obstacle cell

Domain Representation

Domain Implementation

• particles

Particle_Lines

• cell types

3 possibilities each

update for each time step!!!

cell east west north south

Algorithmic Changes

• extended initialization

• time loop:

– update cell types

– set u,v,p at the free boundary

– perform computations ‚inside‘ the fluid

– set u,v at the free boundary

– update particle positions

Boundary Values

• edges between fluid and empty cells

• edges adjacent to fluid cells

• pressure in surface cells

Boundary Conditions

• equlibrium:

surface tension ↔ surface stress

neglection of surface tension

zero stress components