Directivity of acoustic radiation from sourcesThe radiation properties of acoustic monopoles and dipoles are described, as well as the directivity of radiation from these sources in a free field and in the presence of an absorptive surface. The kinematic effects on source radiation due to translation and rotation are discussed. Experimental measurements of sound from an acoustic monopole in motion and the characteristics of helicopter rotor and propeller noise are reviewed. Several essential concepts required by noise control engineers making measurements of noise from moving sources in the proximity of the ground are introduced.
Document ID
19800006605
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Lansing, D. L. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 10, 2013
Publication Date
August 1, 1979
Publication Information
Publication: AGARD Special Course on Acoustic Wave Propagation