Model for Military Jet Noise Jessica

This study explores an alternative approach using a semi-empirical equivalent simple-source model to analyze and characterize the turbulence-induced aeroacoustic sources from military jet aircraft. Initially the model is a single point source located above a hard plane such that the locations of destructive interference from its mirror image matched the measured interference nulls. This provides useful information about the location of the dominant noise source region from the jet. The model then develops into a superposition of Rayleigh-distributed line arrays of uncorre-lated and correlated monopoles. The model is tested on an extensive set of acoustic data taken on an F-22 Raptor. Although the model's line source characteristics are developed using data from only one measurement plane, it is able to accurately reproduce the radiation at other measurement planes. This equivalent line source matches the current prevailing theory that the sideline radiation is largely due to uncorrelated noise, whereas the correlated sources dominate downstream. In addition , the semi-empirical, simple-source model results corroborate the theory that the peak source location moves upstream with increasing frequency and lower engine conditions. ACKNOWLEDGMENTS I would like to thank everyone who has supported me in my educational endeavors. Thank you Dr. Gee for giving me a research project and dedicating so much time to my success. Thank you Dr. Neilsen for patiently teaching and helping me with how to use your code and correcting this thesis. Thank you Alan Wall for helping me with my code and answering all my random questions. Thank you David Krueger being so cheerful all the time. Thank you for my parents for encouraging me to pursue my dreams and getting an education.