Subsonic and supersonic jets and supersonic suppressor characteristics.

Abstract

The flow and acoustic characteristics over a Mach number range of 0.6 to 1.5 were determined for convergent and parallel flow nozzles with room temperature air. Mean velocity and fluctuating impact and static pressure distributions were investigated. Near- and far-field acoustic measurements were obtained, and overall sound power levels were compared with subsonic theory of Lighthill and supersonic theory of Nagamatsu and Horvay. Flow and acoustic characteristics of single and multiple shroud supersonic suppressors were studied. With 191 tubes and shrouds the overall sound power level for a Mach 1.4 jet was reduced 15.3 and 20.5 db respectively.