Subsonic and supersonic jet noise predictions from statistical source models

Subsonic and supersonic jet noise is determined numerically from statistical source models. The goal is to develop prediction methods for high-speed jet noise for application to aeronautical and space transportation systems. In this framework, a combination of a k-ε turbulence closure with an acoustic analogy provides an interesting way to compute such radiated acoustic fields. Three acoustic analogies are investigated. First, the classical Lighthill theory in combination with Ribner's results is applied to calculate jet mixing noise. The second method relies on the Goldstein-Howes converted wave equation, which is used to improve the predicted supersonic jet mixing noise in the upstream direction. It is necessary to properly account for acoustic wave convection, and then, one finds that the Doppler factor features an exponent of -3 in the associated power law. A model based on the Ffowcs Williams-Maidanik analysis then is developed to estimate the Mach-wave noise component that dominates forward arc radiation when the convection Mach number is supersonic. Comparisons between aerodynamic and calculated 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.