The influence of windtunnel walls on discrete frequency noise
Abstract
This paper describes an analytical model that can be used to examine the effects of windtunnel walls on discrete frequency noise. First, a complete physical model of an acoustic source in a wind tunnel is described, and a simplified version is then developed. This simplified model retains the important physical processes involved, yet it is more amenable to analysis. Second, the simplified physical model is formulated as a mathematical problem. An inhomogeneous partial differential equation with mixed boundary conditions is set up and then transformed into an integral equation. The integral equation has been solved with a panel program on a computer. Preliminary results from a simple model problem will be shown and compared with the approximate analytic solution.
 Publication:

OrbitRaising and Maneuvering Propulsion: Research Status and Needs
 Pub Date:
 October 1984
 Bibcode:
 1984aiaa.confR....M
 Keywords:

 Aeroacoustics;
 Duct Geometry;
 Noise (Sound);
 Wind Tunnel Walls;
 Computer Programs;
 Green'S Functions;
 Helmholtz Equations;
 Integral Equations;
 Mach Number;
 Monopoles;
 Partial Differential Equations;
 Acoustics