Abstract
Collimated supersonic flows are present in many different astrophysical contexts ranging from Young Stellar Objects to Active Galactic Nuclei. Simulations of these flows have to take into account several different physical effects like, for example, radiative losses in jets from Young Stellar Objects or relativistic effects in jets from Active Galactic Nuclei. These simulations have to address the issues of the jet formation, collimation and propagation and I will give an overview of their main problems and results.