Stellar winds and mass accreation are presented as important examplesof astrophysical flows. Numerical tools to compute these flows areintroduced. In excercises, students can simulate and visualize suchflows. I discuss transsonic flows, shock physics, and the dynamicalinfluence of radiation and magnetic fields on cosmic plasmae.

Supernovae and gamma-ray bursts are driven by the gravitationalcollapse of heavy stars. Why collapses a star, how canthe gained energy be used to drive the explosion?Neutrinos play an important role in this context. Besidesgravitational waves they are the only observable quantity of theexplosion. The theory and the numerics of gasdynamics and radiationtransport is discussed.