Vern G. Rollin
An experimental investigation was conducted in order to determine the effect of jet temperature on jet-noise generation. Jet pressure ratios from 1.3 to 1.9 and temperatures from 80 degrees to 1000 degrees F were used. Results showed that sound power can be adequately predicted by the Lighthill parameter based on ambient temperature over the range of temperatures investigated. The dimensionless frequency spectra of the jet was shown to be affected by temperature; increasing jet temperature resulted in a shift of acoustic energy from high to low Strouhal numbers. Shifts in the jet spectra were explained on the basis of the effect of temperature on the spreading characteristics of the jet, and a method of correcting the spectra for jet temperature was presented.
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