Accession Number : ADA140753

Title :   Measurements of the Low Wavenumber Wall Pressure Spectral Density during Transition on a Flat Plate.

Descriptive Note : Technical rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE ACOUSTICS AND VIBRATION LAB

Personal Author(s) : Gedney,C J ; Leehey,P

PDF Url : ADA140753

Report Date : Apr 1984

Pagination or Media Count : 35

Abstract : Experimental measurements of the low-Mach number wall pressure spectra density in the transition region are currently carried out in our laboratory. The six element (B&K Model No. 4144) microphone array used by Farabee and Geib was used as the wavenumber filtering apparatus and flush mounted on an open test section identical to that used by Jameson. A technique of conditional sampling on signals was used to determine the characteristics of the transitional flow. The frequency spectrum of the microphone array output was computed for uniform shading, Chebyshev shading and binomial shading. A detailed update on our progress is enclosed. The preliminary results indicate that there is no significant measurable difference in the low wavenumber wall pressure spectrum density for a transitional boundary layer as compared to a fully turbulent boundary layer. (Author)

Descriptors :   *Boundary layer transition, Walls, Pressure measurement, Flat plate models, Wind tunnel tests, Microphones, Arrays, Frequency response

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE