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Passive hypervelocity boundary layer control using an acoustically absortive surface

Citation

Rasheed, Adam (2001) Passive hypervelocity boundary layer control using an acoustically absortive surface. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-08192001-143746

Abstract

A series of exploratory boundary layer transition experiments was performed on a sharp 5.06 degree half-angle round cone at zero angle-of-attack in the T5 Hypervelocity Shock Tunnel in order to test a novel hypersonic boundary layer control scheme. Recently performed linear stability analyses suggested that transition could be delayed in hypersonic boundary layers by using an ultrasonically absorptive surface that would damp the second mode (Mack mode). The cone used in the experiments was constructed with a smooth surface on half the cone (to serve as a control) and an acoustically absorptive porous surface on the other half. It was instrumented with flush-mounted thermocouples to detect the transition location. Test gases investigated included nitrogen and carbon dioxide at M = 5 with specific reservoir enthalpy ranging from 1.3 MJ/kg to 13.0 MJ/kg and reservoir pressure ranging from 9.0 MPa to 50.0 MPa. Detailed comparisons were performed to insure that previous results obtained in similar boundary layer transition experiments (on a regular smooth surface) were reproduced and the results were extended to examine the effects of the porous surface. These experiments indicated that the porous surface was highly effective in delaying transition provided that the hole size was significantly smaller than the viscous length scale.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:boundary layer control; hypervelocity boundary layer control; laminar boundary layer; porous surface
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Hornung, Hans G.
Thesis Committee:
  • Shepherd, Joseph E. (chair)
  • Leonard, Anthony
  • Hornung, Hans G.
  • Colonius, Timothy E.
Defense Date:19 January 2001
Author Email:arasheed (AT) galcit.caltech.edu
Record Number:CaltechETD:etd-08192001-143746
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-08192001-143746
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3168
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:06 Sep 2001
Last Modified:26 Dec 2012 02:57

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