Arndt, Roger E. A.Long, Dean F.2012-08-142012-08-141984-03https://hdl.handle.net/11299/131283The objectives of the Minnesota study were to determine the nature of acoustic radiation from turbulent jets, with both Reynolds and Mach number similitude. Acoustic data were to include intensity, directivity, spectra and narrowband spatial coherence. Emphasis in the initial study was to be on naturally developing jets. A second phase of the program was to be aimed at artificially excited jets. In order to carry out the experimental program as originally envisioned, a special test facility had to be constructed. This test rig had to produce jets of varying diameter, with minimal turbulence levels at the nozzle erlt and be essentially free of acoustic contamination. As it turns out, the latter requirement was essential to the successful completion of the project. The desire to model high subsonic Mach number at low Reynolds number necessitated high speed jets of very small diameter. The high frequency content in these jets necessitated that special emphasis be placed on bothen-USReport