Water injection effects on hot supersonic jet noise

Abstract

The effects of temperature both on supersonic jet noise with water injection (used for noise reduction) and on the efficiency of the method are investigated. The location of injection varies from 1.5 D to 15 D while the other parameters remain fixed to their optimum values. One notices better overall noise level reductions by injecting close to the nozzle exit. Moreover spectral analysis emphasizes that attenuation in high and low frequencies depends on the location of injection. Finally, the jet temperature does not greatly affect the efficiency of this method as the measured attenuation is similar to that encountered with supersonic jets with ambiant temperature.