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Stability of hypersonic boundary-layer flows with chemistryThe effects of nonequilibrium chemistry and three dimensionality on the stability characteristics of hypersonic flows are discussed. In two-dimensional (2-D) and axisymmetric flows, the inclusion of chemistry causes a shift of the second mode of Mack to lower frequencies. This is found to be due to the increase in size of the region of relative supersonic flow because of the lower speeds of sound in the relatively cooler boundary layers. Although this shift in frequency is present in both the equilibrium and nonequilibrium air results, the equilibrium approximation predicts modes which are not observed in the nonequilibrium calculations (for the flight conditions considered). These modes are superpositions of incoming and outgoing unstable disturbances which travel supersonically relative to the boundary-layer edge velocity. Such solutions are possible because of the finite shock stand-off distance. Their corresponding wall-normal profiles exhibit an oscillatory behavior in the inviscid region between the boundary-layer edge and the bow shock. For the examination of three-dimensional (3-D) effects, a rotating cone is used as a model of a swept wing. An increase of stagnation temperature is found to be only slightly stabilizing. The correlation of transition location (N = 9) with parameters describing the crossflow profile is discussed. Transition location does not correlate with the traditional crossflow Reynolds number. A new parameter that appears to correlate for boundary-layer flow was found. A verification with experiments on a yawed cone is provided.
Document ID
19940005996
Document Type
Conference Paper
Authors
Reed, Helen L.
(Arizona State Univ. Tempe, AZ, United States)
Stuckert, Gregory K.
(Arizona State Univ. Tempe, AZ, United States)
Haynes, Timothy S.
(Arizona State Univ. Tempe, AZ, United States)
Date Acquired
August 16, 2013
Publication Date
April 1, 1993
Publication Information
Publication: AGARD, Theoretical and Experimental Methods in Hypersonic Flows
Subject Category
Aerodynamics
Accession Number
94N10451
Funding Number(s)
CONTRACT_GRANT: F49620-88-C-0076
Distribution Limits
Public
Copyright
Other
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