SUBSONIC AND SUPERSONIC JET NOISE PREDICTIONS FROM STATISTICAL SOURCEMODELS

Subsonic and supersonic jet noise is determined numerically from stati stical source models, The goal is to develop prediction methods for hi gh-speed jet noise for application to aeronautical and space transport ation systems, In this framework, a combination of a k-epsilon turbule nce closure with an acoustic analogy provides an interesting way to co mpute such radiated acoustic fields, Three acoustic analogies are inve stigated, First, the classical Lighthill theory in combination with Ri bner's results is applied to calculate jet mixing noise, The second me thod relies on the Goldstein-Howes convected wave equation, which is u sed to improve the predicted supersonic jet mixing noise in the upstre am direction, It is necessary to properly account for acoustic wave co nvection, and then, one finds that the Doppler factor features an expo nent of -3 in the associated power law, A model based on the Ffowcs Wi lliams-Maidanik analysis then is developed to estimate the Mach-wave n oise component that dominates forward are radiation when the convectio n Mach number is supersonic. Comparisons between aerodynamic and calcu lated acoustic results on the one hand, and available measurements on the other hand, are carried out. It is shown that the last two models yield improved supersonic jet mixing noise predictions.