Accession Number : AD0422750

Title :   SURFACE PRESSURE FLUCTUATIONS PRODUCED BY BOUNDARY LAYER TURBULENCE,

Corporate Author : CONTROL DATA CORP MELVILLE N Y TRG DIV

Personal Author(s) : Gardner,Sheldon

Report Date : OCT 1963

Pagination or Media Count : 33

Abstract : Surface pressure fluctuations produced by boundary layer turbulence developed above a rigid plane surface are investigated theoretically. For an incompressible flow which obeys the Navier-Stokes equations, the boundary pressure is determined by a volume integration over quadrupole sources. Three different classes of source terms may be identified. These involve second, third, and fourth order velocity correlations. The contribution of the fourth order or turbulence-turbulence terms to the boundary pressure cross spectral density at high frequencies is obtained. The results show that the turbulence-turbulence boundary pressure sources are located at an effective height, and travel with an effective convection speed, both of which depend upon frequency and the shape of the mean velocity profile. At high frequencies, the pressure spectrum is found to be roughly proportional to the sixth power of the free stream velocity, and to the inverse cube of the frequency. Finally, the effect of the finite size of the transducer upon the measured boundary pressure spectrum is discussed. (Author)

Descriptors :   (*BOUNDARY LAYER, TURBULENCE), (*PRESSURE, SURFACES), (*TURBULENT BOUNDARY LAYER, PRESSURE), SURFACE PROPERTIES, THEORY, INCOMPRESSIBLE FLOW, FLUID FLOW, VOLUME, NUMERICAL INTEGRATION, VELOCITY, HIGH FREQUENCY, CONVECTION, EXPERIMENTAL DATA, TRANSDUCERS, MEASUREMENT

Distribution Statement : APPROVED FOR PUBLIC RELEASE