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The reduction of numerical entropy generated by unsteady Shockwaves

Published online by Cambridge University Press:  04 July 2016

C. B. Allen
C. B. Allen*
Affiliation:
Department of Aerospace EngineeringUniversity of BristolBristol, UK
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Abstract

The computation of slowly moving Shockwaves is considered. A numerical error is introduced into the solution during an explicit computation, which results in the generation of spurious entropy. The generation of this spurious entropy and its effect on the pressure wave in Euler flows is examined, in one dimension by considering a moving shock in a constant area duct, and in two dimensions by considering an unsteady aerofoil flow. An efficient temporal discretisation is presented, whose advantages over the explicit scheme are two-fold. First, the numerical entropy generation due to shock motion is eliminated, and second, the CPU requirements for a two-dimensional unsteady computation are reduced by a factor of five from that required for the explicit scheme, for no loss of accuracy.

Type
Research Article
Information
The Aeronautical Journal , Volume 101 , Issue 1001 , January 1997 , pp. 9 - 16
Copyright
Copyright © Royal Aeronautical Society 1997 

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