Predictions of the Acoustic Nearfield on a Carrier Deck

On a carrier deck, navy personnel operate in close proximity to high-speed jets. They are, therefore, exposed to high intensity jet noise resulting in possible severe loss of hearing. The objective of the project is to develop jet noise prediction capability for quantitative assessment of the acoustic environment on an active carrier deck. Such assessment would allow the identification of noise hot spots to be avoided. Jet noise consists of three principal components; the fine-scale turbulence noise, the large turbulence structures noise and the broadband shock-cell noise. For military jets, the large structures noise is most intense and dominant. It is the focus of this project. Specifically, the aim is to develop a physics-based prediction method. It is known that large turbulence structures are spatially and temporally coherent. The noise is highly direction. The mechanism is Mach wave radiation. All these important characteristics will be incorporated into the model prediction theory. The theory will follow the highly successful Tam and Auriault (1999) fine-scale turbulence noise theory with the characteristics of fine scale turbulence replaced by those of the large turbulence structures. The Green’s function method will be used to propagate noise from source to the near and far field.