Accession Number : AD0758254

Title :   A Study of Narrow Band Noise Generation by Flow Over Ventilated Walls in Transonic Wind Tunnels,

Corporate Author : NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CALIF

Personal Author(s) : Woolley,James P. ; Karamcheti,Krishnamurty

Report Date : FEB 1973

Pagination or Media Count : 88

Abstract : The report is concerned with the problem of environmental noise in transonic wind tunnels with ventilated, or perforated, walls. A brief critical review of past experimental investigations of such sounds is given. It is indicated that the instability of the separated shear layer over the cavities in a perforated wall should be the main agency for sound generation. A stability analysis of a nonparallel shear flow is undertaken. Relations such as the Strouhal numbers and minimum breadths, are given in terms of wind-tunnel aerodynamic parameters. (Author Modified Abstract)

Descriptors :   (*TRANSONIC WIND TUNNELS, *NOISE), NARROWBAND, ORIFICES, ACOUSTIC PROPERTIES, STABILITY, SHEAR STRESSES, FLOW FIELDS, TURBULENCE

Subject Categories : Test Facilities, Equipment and Methods
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE