Abstract:
In order to improve the accuracy of high frequency measurement of jet far field noise, the factors affecting the high frequency measurement of jet noise have been systematically studied based on the experimental method of the strict jet noise simulator test equipment. These factors contain: the directivity of microphone, the frequency response characteristics of microphone, the influence of microphone protective cover, the noise floor of microphone and the effect of atmospheric absorption, etc. The experimental comparison and quantitative analysis of each influence factor have been carried out. Recommendations and correction methods for high frequency jet noise measurement are given. Finally, the location of geometric far field, which is very important for the accurate measurement of the high frequency radiation characteristics of far field jet noise, is proposed based on experimental measurement results.