Amplification and generation of turbulence during self-gravitating collapse

The formation of astrophysical structures, such as stars, compact objects but also galaxies, entail an,enhancement densities by many orders magnitude which occurs through gravitational collapse. role played turbulence during this process is important. Turbulence generates density fluctuations, exerts a support against gravity and possibly delivers angular momentum. How exactly behave the collapse get amplified remains matter investigation. Spherical averaging fluid equations carried out, leading to 1D that describe evolution mean quantities in particular radial velocity well transverse turbulent velocities. These differ from ones usually employed literature. We then perform series 3D numerical simulations collapsing clouds for wide range thermal supports with two polytropic equation state, $P \propto \rho^\Gamma$, $\Gamma=1$ 1.25. For each we using spherically averaged same initial conditions. By performing detailed comparison between simulations, can analyse great details observed behaviours. Altogether find approaches agree remarkably demonstrating validity inferred although when initially strong, major deviations spherical geometry certainly preclude quantitative comparisons. comparisons lead us an estimate dissipation parameter low, found be good agreement previous non self-gravitating supersonic turbulence. abridged.