Accession Number:

ADA063710

Title:

Low Wavenumber Levels of Turbulent Boundary Layer Wall Pressure Fluctuations in Zero and Adverse Gradients

Descriptive Note:

Final rept. Mar 1976-Sep 1977

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE ACOUSTICS AND VIBRATION LAB

Personal Author(s):

• Moeller, M.
• Leehey, P.
• Martin, N. C.

Report Date:

1978-09-01

Pagination or Media Count:

89.0

Abstract:

The low wavenumber components of the turbulent boundary layer wavenumber frequency spectrum of wall pressure fluctuations were measured with two flush-mounted rectangular plates having approximately clamped boundary conditions. The plates were designed to provide low wavenumber measurements at higher frequencies and wavenumbers than previous plate experiments in order to provide data comparable with measurements made by Farabee and Geib 7 with an array of flush-mounted microphones. The low wavenumber measurements were made in the M.I.T. low noise low turbulence subsonic wind tunnel under zero and adverse pressure gradient conditions. When nondimensionalized on outer boundary layer variables the adverse pressure gradient data do not exhibit increased levels from those of the zero pressure gradient data. The zero pressure gradient data are in good agreement with the levels reported by Farabeen and Geib 7 for the same nondimensional frequency and wavenumber range.

Descriptors:

• *TURBULENT BOUNDARY LAYER
• ACOUSTIC MEASUREMENT
• FLAT PLATE MODELS
• MARINE ENGINEERING
• PRESSURE GRADIENTS
• STRUCTURAL RESPONSE
• SUBSONIC WIND TUNNELS
• VIBRATION
• WALLS

Subject Categories:

• Marine Engineering
• Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE