A new prescription for viscosity in Smoothed Particle Hydrodynamics

Department of Physics and Astronomy, University of Wales, Cardiff, CF2 3BY, Wales, UK

Corresponding author: Send offprint request to: S. Watkins, e-mail: S.Watkins@astro.cf.ac.uk

Received: 2 October 1995
Accepted: 21 February 1996

Abstract

Smoothed particle hydrodynamics (SPH) is a particle method for modelling hydrodynamical flows that has been successfully applied to a wide range of astrophysical problems. One of its main weaknesses, however, has been its inability to treat viscosity in a rigorous manner. We present a new method that can be used to solve the Navier-Stokes equation for an arbitrary viscosity. We compare the accuracy of the method to alternative methods for treating viscosity in SPH, and apply the method to a series of tests for which there exist analytic solutions. We find that the new method is significantly more accurate than other existing methods, computationally efficient, and that the results of simulations carried out using the method are in excellent agreement with the theory.