J. Whitmire, S. Sarkar

Acoustic analogy calculations and direct computations of sound generated by unsteady fluid motion are performed. The acoustic analogy calculation is performed for two types of the equivalent acoustic source in the Lighthill analogy, first, a prescribed spatially periodic, time harmonic source and, second, a spatially periodic, unsteady simulation of isotropic turbulence. It is analytically and numerically shown that spatial periodicity of the equivalent acoustic source leads to sound radiation with octupole efficiency. A third problem, sound radiated from a forced compact region of isotropic turbulence, is investigated by direct simulation of the compressible flow equations in a domain that contains the source and the far-field. The results from the direct computation regarding the amplitude, wavelength and frequency of the far-field, acoustic pressure is consistent with the monopole type forcing used here.

First Joint CEAS/AIAA Aeroacoustics Conference, München, 1995

Conference Paper

englisch

21,0 x 29,7 cm, 11 Seiten

DGLR-Bericht, 1995, 1995-01, First Joint CEAS/AIAA Aeroacoustics Conference - Proceedings; S.263-273; 1995; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroacoustics

Bibliothek

1995