The Use of Non-Spherical Kernels in Smooth Particle Hydrodynamics

Abstract

A general expression for the momentum equation in the Smooth Particle Hydrodynacis approximation is derived for an arbitrary kernel, and compared with its spherical counterpart for various degrees of ellipsoidicity. For such an ellsipsoidal kernel the contribution to the adiabatic acceleration from different parts of the kernel is studied, and how the noise level in an interaction varies with the shape of the kernel. The two body interaction involving kernels with different shapes is also briefly discussed, as well as the conservation problems in the sum over the two body interactions.