Numerical simulation of the effect of a low bypass cooling stream on supersonic jet noise

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

Jet flow and noise simulations are performed for realistic tactical aircraft engine nozzles with a cooling fan-stream. A hybrid approach combining time-accurate CFD simulations and the acoustic analogy is used. A multiblock structured mesh topology is used to represent the complex nozzle geometry, including the faceted inner contours representing flaps and seals, fan-core splitter and the finite nozzle thickness. A reasonable agreement of the predicted noise spectra with the acoustic measurement is found to reach to St ≈ 2.0. The results show how the bypass cooling flow introduces a low-temperature, low-speed buffer between the heated high-speed core jet and the stationary ambient. This initial buffer reduces the velocity gradient in the jet turbulent mixing layer near the nozzle exit. In turn, this results in a reduction in medium shear layer, which results in a reduction of the turbulent mixing noise when the same core temperature is retained. The difference diminishes after full mixing appears further downstream. As a further analysis tool, the Proper Orthogonal Decomposition is applied to the beamformed far-field acoustic pressure and the near-field pressure fluctuations obtained from the unsteady CFD computations. The dominant modes show a wave packet form. When inserted into the pressure wave equation, the wave packets reproduce well the Mach wave radiation in terms of its phase, wavelength and radiation direction.

Original languageEnglish (US)
Title of host publication52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014
PublisherAmerican Institute of Aeronautics and Astronautics Inc.
ISBN (Print)9781624102561
StatePublished - Jan 1 2014
Event52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014 - National Harbor, MD, United States
Duration: Jan 13 2014Jan 17 2014

Publication series

Name52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014

Other

Other52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014
CountryUnited States
CityNational Harbor, MD
Period1/13/141/17/14

All Science Journal Classification (ASJC) codes

  • Space and Planetary Science
  • Aerospace Engineering

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    Du, Y., & Morris, P. J. (2014). Numerical simulation of the effect of a low bypass cooling stream on supersonic jet noise. In 52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014 (52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014). American Institute of Aeronautics and Astronautics Inc..