LES-RANS of installed ultra-high-bypass-ratio coaxial jet aeroacoustics with flight stream

Research output: Contribution to journalArticlepeer-review

Authors

Colleges, School and Institutes

External organisations

  • University of Cambridge

Abstract

Using large-eddy simulation-Reynolds-averaged Navier-Stokes (LES-RANS), this paper studies a round coaxial nozzle with an ultra-high bypass ratio of 15, with and without a wing-flap geometry. Depending on engine placement, the nozzle can become extremely close to the wing-flap geometry, introducing strong installation effects. Two different flap deflections of 8 and 14 deg are contrasted with an isolated round nozzle. A flight stream is applied and an Ffowcs Williams-Hawkings (FWH) surface placement procedure for installed jets is proposed. Impressive agreement with available experimental data is economically achieved for far-field overall sound pressure level and spectra as well as near-field spectra. The LES provides a wider range of polar and azimuthal angles at 1 deg increments, providing one of the most detailed acoustics data sets to date. The installed cases generate up to 20 dB more noise at mid-low frequencies due to large flap trailing edge sources. Additional sources are introduced by the interaction of the flight stream with the lifting surfaces. Second-order space-time correlations reveal length and time scales in the flow. Fourth-order space-time correlations indicate increasing magnitudes of the dominant noise source components with increasing flap angle. The three-dimensional unsteady data set produced should lead to improved acoustics models.

Details

Original languageEnglish
Pages (from-to)1215-1236
Number of pages22
JournalAIAA Journal
Volume57
Issue number3
Early online date2 Jan 2019
Publication statusPublished - Mar 2019

ASJC Scopus subject areas