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Stability of Temporally Evolving Supersonic Boundary Layers over Micro-Cavities for Ultrasonic Absorptive Coatings

Brès, Guillaume A. and Colonius, Tim and Fedorov, Alexander V. (2008) Stability of Temporally Evolving Supersonic Boundary Layers over Micro-Cavities for Ultrasonic Absorptive Coatings. In: 5th AIAA Theoretical Fluid Mechanics Conference, 23–26 June 2008, Seattle, WA.

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Ultrasonic absorptive coatings, consisting of regularly-spaced arrays of micro-cavities, have previously been shown to effectively damp second-mode instability for the purpose of delaying transition in hypersonic boundary layers. However, previous simulations and stability analysis have used approximate porous-wall boundary conditions. Here we investigate the feasibility of using direct numerical simulation to directly compute the hypersonic boundary layer including the micro-cavities. In order to keep the problem computationally tractable, we restrict our attention to the two-dimensional case (which is relevant since the second-mode is initially two dimensional), and we show that temporally evolving layers display qualitatively similar behavior to spatially developing boundary layer and instabilities. We validate the numerical method by comparing the simulation results to temporal linear stability analysis of the (frozen) velocity and temperature profiles from the direct numerical simulation. Two-dimensional linear simulations of the boundary layer on a flat plate and over a porous coating are performed, and it is shown that the presence of the cavities attenuates the instability waves, as expected from theory.

Item Type:Conference or Workshop Item (Paper)
Related URLs:
URLURL TypeDescription Paper Paper
Brès, Guillaume A.0000-0003-2507-8659
Colonius, Tim0000-0003-0326-3909
Additional Information:© 2008 by G. A. Bres, T. Colonius, & A. V. Federov. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Published Online: 14 Jun 2012. The authors would like to acknowledge contributions to this work by Norm Malmuth, whose passionate work on diverse topics, including UAC, and generosity to his collaborators will be sorely missed. This work was supported by the Air Force of Scientific Research under Contract FA9550-06-C-0097.
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-06-C-0097
Subject Keywords:Theoretical Fluid Mechanics
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Other Numbering System NameOther Numbering System ID
AIAA Paper2008-4337
Record Number:CaltechAUTHORS:20190718-165126067
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97257
Deposited By: Melissa Ray
Deposited On:22 Jul 2019 20:41
Last Modified:16 Nov 2021 17:30

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