Astrophysical Turbulence

Simulations of disk galaxies

disk galaxy

Disk galaxies are probably the most complex objects in astrophysics.


They are composed of dark matter, gas, and stars. The physics involves gravity, turbulent gas dynamics, heating and cooling, and magnetic fields. In contrast to the size of a typical disk galaxy, which is of the order 10 kpc, many important processes operate on tiny scales. Examples are cooling instabilties (about 10 pc) and, of course, star formation (subparsec scales).


Even with the largest available supercomputers, exact computations are infeasible. For this reason, we need subgrid scale models for processes below the numerical grid resolution.

 

Together with his former PhD student Harald Braun, Wolfram Schmidt developed a model framework for galaxy simulations that is based on the large eddy simulation technique in combination with adaptive mesh refinement. This approach allows for a physically and numerically consistent treatment of turbulence, which in turn helps to infer the local star formation rate and the turbulent pressure produced by supernova-driven shock waves.

 

For more information, see