Influence of Wind Tunnel Noise on the Location of Boundary-Layer Transition on a Slender Cone at Mach Numbers from 0.2 to 5.5. Volume I. Experimental Methods and Summary of Results.
Final rept. 26 Jan 1970-8 Apr 1977
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
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A study was conducted to investigate the effects of wind tunnel noise on the location of boundary-layer transition. The study was carried out by conducting experiments on a particular slender, highly polished cone having an included angle of 10 deg. Wind tunnel noise levels were measured in the test section by flush-mounted microphones imbedded in the cone surface. The measurement of boundary-layer transition location was made using either a traversing pitot pressure probe in contact with the cone surface or the flush- mounted microphones. The experiments were carried out in 23 different subsonic, transonic, and supersonic wind tunnels over a range of Mach numbers from 0.2 to 5.5 and a unit Reynolds number range from 1.0 to 7.0 million per foot, the bulk of the data being obtained for a range from 2.0 to 4.0 million per foot. The results clearly show a strong influence of wind tunnel noise on boundary-layer transition location correlatable with overall root-mean-square noise levels. Because the noise level generally varied with Mach number and unit Reynolds number, the unit Reynolds number was found to have little effect on transition Reynolds number.
- Fluid Mechanics