This is a simulation of a strong pressure/temperature gradient in a huge structure with obstacles and an outlet on the top. The initial conditions are set up, such that the gas at the bottom has a temperature of 2000 K and the gas above a temperature of 300 K. Due to the pressure gradient strong shocks evolve. These shocks are then reflected at the boundaries. In addition background-gravity was switched on, so the warm gas starts slowly to rise up. The whole simulation shown in the movie lasts ~5 s in real-time. The structure has a diameter of ~50 m.