Comments on smoothed particle hydrodynamics

Smoothed Particle Hydrodynamics (SHP) is shown to be a good method for the calculation of hydrodynamic and MHD flows in both two and three dimensions with relatively little numerical effort. It is found that while large scale flows and magnetic fields can be reproduced well, spatial resolution is limited and the description of small scale structures is not sufficient. It is also shown that unphysical effects may arise from an improper choice of the smoothing function, which will yield artificial structures. A new smoothing function is proposed which does not suffer from this defect, which is thought to have influenced results of protostellar fission studies published to date.