The effect of solid surfaces on turbulent jet noise

✍ Scribed by C. Smith; P.W. Carpenter

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 640 KB
• Volume: 185
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.1995.0388

✦ Synopsis

Lighthill's acoustic analogy is applied to the problem of calculating the sound radiated by unit volume of jet-type shear-layer turbulence near a solid surface. The ensemble-averaged basic directivity patterns of the sound generated by randomly orientated longitudinal and lateral quadrupoles near a rigid plane are calculated, and are found to be very different for the two types of quadrupole. A method of modelling the acoustic sources, due to Ribner, is extended to the present case, enabling the basic directivity pattern to be calculated. The effect of the solid surface is found to depend strongly on the source frequency, and a method for estimating the source frequency in an actual turbulent shear flow is developed. The theory is applied to a plane two-dimensional wall jet, and predictions of some basic aero-acoustic characteristics are obtained.