Conference_programme: 4.2 - Aircraft/Helicopter Noise

Lecture: Noise prediction of a high aspect ratio jet interacting with an embedded surface using CFD mean flow within a Rapid-Distortion Theory framework

Author(s): Sassanis Vasileios, Afsar Mohammed, Sescu Adrian

Summary:
Jet surface interaction (JSI) noise has become increasingly important for the next generation commercial near-sonic and supersonic aircrafts owing to highly integrated designs of compact propulsion systems, embedded within the wing structure. Three noise components are generally observed when the exhaust gases breakdown into turbulence: i) broadband jet noise, ii) scrubbing noise at the surface and iii) trailing/leading edge interaction noise. This work aims to investigate item (iii) for a high-aspect ratio (8:1) jet exhaust operating at Maj of 0.98, (referred to as SP 7 and with an acoustic Maa of 0.9). The model is based on a recent development in Rapid-distortion theory of turbulence (Goldstein, Leib & Afsar 2017, vol. 824, pp. 477-512) in which mean flow inputs are obtained from a steady Reynolds-Averaged Navier Stokes Simulations (RANS) calculation using the commercially available Fluent software. For validation purposes, we compare this model to the hybrid noise prediction obtained using an in-house Large Eddy Simulations (LES) code that is able to calculate the near field turbulence and project it to the far field, using either the traditional approach of Ffowcs-Williams Hawking’s equation solved on a near field control surface with open ends, or by solving the full nonlinear Euler equations with source terms.

Corresponding author

Name: Mr Vasileios Sassanis

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Country: United States