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Optimal Growth in Hypersonic Boundary LayersThe linear form of the parabolized linear stability equations is used in a variational approach to extend the previous body of results for the optimal, nonmodal disturbance growth in boundary-layer flows. This paper investigates the optimal growth characteristics in the hypersonic Mach number regime without any high-enthalpy effects. The influence of wall cooling is studied, with particular emphasis on the role of the initial disturbance location and the value of the spanwise wave number that leads to the maximum energy growth up to a specified location. Unlike previous predictions that used a basic state obtained from a self-similar solution to the boundary-layer equations, mean flow solutions based on the full Navier-Stokes equations are used in select cases to help account for the viscous- inviscid interaction near the leading edge of the plate and for the weak shock wave emanating from that region. Using the full Navier-Stokes mean flow is shown to result in further reduction with Mach number in the magnitude of optimal growth relative to the predictions based on the self-similar approximation to the base flow.
Document ID
20170000450
Acquisition Source
Langley Research Center
Document Type
Reprint (Version printed in journal)
Authors
Pedro Paredes ORCID
(Langley Research Center Hampton, Virginia, United States)
Meelan M Choudhari ORCID
(Langley Research Center Hampton, Virginia, United States)
Fei Li
(Langley Research Center Hampton, Virginia, United States)
Chau-Lyan Chang ORCID
(Langley Research Center Hampton, Virginia, United States)
Date Acquired
January 17, 2017
Publication Date
June 17, 2016
Publication Information
Publication: AIAA Journal
Publisher: American Institute of Aeronautics and Astronautics
Volume: 54
Issue: 10
Issue Publication Date: October 1, 2016
ISSN: 0001-1452
e-ISSN: 1533-385X
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
NF1676L-23110
Funding Number(s)
WBS: 109492.02.07.01.01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
Compressible boundary layer
Freestream Mach Number
Shock layers
Leading edges
Incompressible flow
Navier Stokes equations
Enthalpy
Parabolized stability equations
Kinetic energy
Compressibility effect

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