A METHOD OF ASSESSING THE EFFECTS OF ARTIFICIAL DISSIPATION IN NAVIER-STOKES CODES

Abstract

A new method of estimating the extent of the artificial dissipation effects in any solution obtained with a Navier-Stokes flow solver is described. Rather than recalculating the flow on a more refined grid, the solver may be used on the same grid to calculate the flow of an artificially dissipative fluid, which is a fluid having dissipative properties which arise entirely from the solution method itself. This is done by setting the viscosity and heat conduction coefficients in the Navier-Stokes solver to zero everywhere in the flow, while at the same time applying the usual boundary conditions at solid boundaries. An artificially dissipative flow solution will be found where the dissipation effects depend entirely on the solver itself. By comparing this solution with that obtained on the same grid with the solver working in its normal mode, one can estimate whether further grid refinement is required, without necessarily producing an extensive series of solutions on different grids.