The underying physical experiment is a Mach 3 flow, coming from the left, through a tube with a forward facing step in 3D. In this video you can see the numerical solution of the compressible, timedependent Euler equations in 3D. The numerical scheme is a finite volume scheme on a dynamically, locally refined, irregular mesh. The computation have been done on a parallel computer. One single color indicates the domain for one processor. Due to the timedependent, adaptive grid refinement, the scheme looses its load balancing. After some timesteps the nodes have to be redistributed to obtain again a good load balancing.