Further Measurements of Intensity, Scale, and Spectra of Turbulence in a Subsonic Jet

As an extension to the data reported in Technical Note 3561, hot-wire-anemometer measurements of the intensity, scale, and spectra of turbulence in a 3.5-inch-diameter free subsonic jet were made for downstream distances from 8 to 20 jet diameters. The results show that the eddy size increased with distance from the jet nozzle until a maximum was reached. The position of this maximum depended upon the distance from the jet centerline. After reaching the maximum, the eddy decreased uniformly in size with distance from the nozzle. The nondimensional mean-velocity profiles were nearly similar in a region from 12 to 20 jet diameters from the nozzle. Corresponding similarity in intensity of turbulence profiles, however, was not observed as far as 20 jet diameters downstream of the nozzle.