Noise Source Distribution of Coaxial Subsonic Jet-Short-Cowl Nozzle

Authors

  • Odenir de Almeida Federal University of Uberlândia - UFU Faculty of Mechanical Engineering - FEMEC
  • João Roberto Barbosa Technologic Institute of Aeronautics - ITA, Sao Jose dos Campos, Sao Paulo, 12232030, Brazil
  • Juan Battaner Moro Institute of Sound and Vibration Research, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
  • Rodney Harold Self Institute of Sound and Vibration Research, University of Southampton, Highfield, Southampton SO17 1BJ, UK.

Keywords:

Aeroacoustics, Acoustic analogy, Turbulence, Noise, Nozzle.

Abstract

The noise source distribution of a short-cowl coaxial jet operating at different velocity ratios is described in this work. This was motivated by an ongoing research about noise prediction of coaxial jets through Acoustic Analogy with purposes of industrial engine application. This research has been carried out between Universidade Federal de Uberlândia (UFU), Brazil and the Institute of Sound and Vibration Research (ISVR) at Southampton University, UK. The numerical approach employed is originally based on Lighthill Acoustic Analogy. This technique, although likely known, is associated with an improved energy transfer time-scale, used in the turbulence two-point correlation function, in order to enhance the source model. The source model is coupled with the aerodynamic calculation of flow through turbulence quantities evaluated by using a standard k-ε turbulence modeling. The Computational Fluid Dynamics data have also been used to provide complementary information about the coaxial jet noise production mechanisms. Experimental data were used in order to corroborate the results from the current model. Good agreement has been found, showing that high and low frequency contributors to the radiated noise for low velocity ratio are aggregated in a region about seven to ten secondary diameters downstream, while at higher velocity ratios sources are continuously spread from about one up to ten secondary diameters from the jet exit.

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Published

2014-02-17

Issue

Section

Original Papers