Which state variables are stored in an SPH particle?
mass, position, velocity
How do we compute the density in an SPH simulation?
with a Kernel
What are the simulation steps of a vanilla SPH simulation?
compute particle neighborhoods
update per-particle densities and pressures
compute forces
update velocities and particle positions
Name and describe acceleration data structures for neighbor search!
KD-tree, regular grid
How do we calculate the pressure in the fluid?
with the ideal gas state equation
Why does the flow become less compressible after a pressure gradient step?
Attraction forces
What are potential causes of instability in an SPH simulation?
Pressure and viscosity forces
How do we determine the step size for an SPH step?
Courant-Friedrichs-Lewy (CFL) Condition:
Δ𝑡 ≤ 𝜆 ℎ/||𝑣𝑚𝑎𝑥||
Would you recommend a regular grid or a Poisson-disk sampling for the initial particle distribution?
Poisson sampling to counteract aliasing
How can we improve the incompressibility of an SPH simulation?
with an iterative SPH solver with repeats the update steps and computes the pressure forces until convergence
What is so challenging about the explicit integration of viscosity in grid-based solvers? Why is the implicit approach preferred?
explicit requires small time steps
Which effects do we forget when not coupling the free traction condition correctly?
coiling and folding
Zuletzt geändertvor 2 Jahren