Report 1991-10

Influence of numerical diffusion in high temperature flow

M. Fey and R. Jeltsch

Abstract: In high temperature flow it is necessary to introduce new physical phenomena to the governing equations. Chemical reactions and vibrational excitation of the molecules lead to inhomogeneous Euler equations with a source term and an additional equation of conservation of mass for each species. From the mathematical point of view we only get additional contact discontinuities for the different species. From the numerical perspective the treatment of the fluxes of partial densities has a large influence on the results. For a given shock-capturing scheme we discuss three methods to compute the fluxes of partial densities for the same total density flux. We compare the numerical diffusion for the different fluxes. In a two-dimensional testcase we illustrate the advantages and disadvantages of these schemes. The third one shows a good resolution of the strong gradients in the mass fractions for this special testcase.

Keywords: chemical reacting flow, numerical diffusion, stagnation point

Paper: Available as PDF (470KB) or as hardcopy to order reports@sam.math.ethz.ch.

Publishing information: Proceedings of the 9th GAMM Conference on Numerical Methods in Fluid Dynamics, 35, (1992), pp. 119-127. Serie: Notes on Numerical Fluid Mechanics. Editors. J.B. Vos, A. Rizzi and I.L. Rhyming