A Study of Narrow Band Noise Generation by Flow Over Ventilated Walls in Transonic Wind Tunnels
NIELSEN ENGINEERING AND RESEARCH INC MOUNTAIN VIEW CA
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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.
- Test Facilities, Equipment and Methods