Localization of Noise Sources in Jets Flowing from Lobed Nozzles

Abstract

The noise of jets formed using conical and lobed nozzles has been measured. The possibility of jet noise reduction by using a lobed nozzle shape has been demonstrated. The localization of noise sources in jets formed using various nozzles has been carried out. A planar 9-beam 54-channel Bruel & Kjaer micro-phone array and Delay-and-Sum Beamforming technique were used. As a result, the position of noise sources in a turbulent jet in one-third octave frequency bands was obtained. The deviation effect of the position of noise sources when using lobed nozzles relative to the standard jet formed by a conical nozzle is demonstrated.