ACCURATE SHOCK CAPTURING BY SELECTION OF A SUITABLE ARITIFICAL VISCOSITY

Document Type : Research Note

Authors

1 Dept . of Mechanical Engineering Tarbiat Modares University

2 Dept . of Mechanical Engineering Iranian,niversity of Science and Technology

Abstract

The addition of a fictitious term, artificial viscosity, into the inviscid Euler equations of fluid dynamics, in order to automatically ''capture" shock waves, is, perhaps, the oldest numerical device in the rel­ atively new field of r.omputational physics and me­ chanics. Many different functional forms for arti-ficial viscosity have been proposed. These forms eontain problem-sensitive-constants that are often set in a somewhat arbitrary manner . The purpose of this work is to choose a suitable fomL to remove
as many of these arbitrary constants as possible.For this purpose, a form presented by Caramana is seleeted. This form has some important proper­ ties, namely1 dissipativity, Galilean invarianee, abil­ ity to distinguish between shock waves, adiabatic compression and turning off completely for rigid mot ion. Properties are enforced to this form by use of a limiter. :'\umerical results show more ac.­ curate shock wave capturing in non-planar spaces, especially in the convergent cases, than in the other forms of artificial viscosity.

Keywords