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Computing unsteady shock waves for aeroacoustic applicationsThe computation of unsteady shock waves, which contribute significantly to noise generation in supersonic jet flows, is investigated. This paper focuses on the difficulties of computing slowly moving shock waves. Numerical error is found to manifest itself principally as a spurious entropy wave. Calculations presented are performed using a third order essentially nonoscillatory scheme. The effect of stencil biasing parameters and of two versions of numerical flux formulas on the magnitude of spurious entropy are investigated. The level of numerical error introduced in the calculation in quantified as a function of shock pressure ratio, shock speed, Courant number, and mesh density. The spurious entropy relative to the entropy jump across a static shock decreases with increasing shock strength and shock velocity relative to the grid, but is insensitive to Courant number. The structure of the spurious entropy wave is affected by the choice of flux formulas and algorithm biasing parameters. The effect of the spurious numerical waves on the calculation of sound amplification by a shock wave is investigated. For this class of problem, the acoustic pressure waves are relatively unaffected by the spurious numerical phenomena.
Document ID
19950057368
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Meadows,, Kristine r.
(NASA Langley Research Center Hampton, VA, United States)
Caughey, David A.
(Cornell University Ithaca, NY, United States)
Casper, Jay
(ViGYAN, Inc. Hampton, VA, United States)
Date Acquired
August 16, 2013
Publication Date
July 1, 1994
Publication Information
Publication: AIAA Journal
Volume: 32
Issue: 7
ISSN: 0001-1452
Subject Category
Aerodynamics
Accession Number
95A88967
Distribution Limits
Public
Copyright
Other

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