Leslie W. Lassiter, Harvey H. Hubbard
naca-tn-2757
Aug 1952
Experimental studies, which were conducted on the ground in still air, were made to evaluate some of the effects of parameters such as jet velocity, density, and turbulence level, as well as jet size, on the noise generated by subsonic jets.
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http://naca.central.cranfield.ac.uk/reports/1952/naca-tn-2757.pdf