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This practical course at the Institute of Computer Science covers time discretisation methods for momentum equations, mass conservation, the Poisson equation, and velocity corrections. Learn about stability criteria, the algorithm for one time step, and debugging strategies for velocity calculations and pressure equations.
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Scientific Computing in Computer Science Institut für Informatik Practical Course SC & V Time Discretisation Dr. Miriam Mehl
Time Discretisation • Euler step for momentum equations • pressure ensures mass conservation • poisson equation • correction of velocities
Time Step – Stability • small reynolds number: dt < dx2 • high reynolds number:dt < dx
Algorithm (One Time Step) • compute time step dt • set boundary values • compute preliminary velocities • solve pressure equation • compute final velocities
Debugging • simple setup: • one(!!!) time step • external forces zero • test preliminary velocities at boundaries • test residual of the pressure equation
Debugging • enhanced setup: • initialize velocities constant butwith nonzero boundary values • test preliminary velocities