CUED Publications database

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

Tyacke, JC and Wang, ZN and Tucker, PG (2019) LES-RANS of installed ultra-high-bypass-ratio coaxial jet aeroacoustics with flight stream. AIAA Journal, 57. pp. 1215-1236. ISSN 0001-1452

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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.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div A > Fluid Mechanics
Div A > Turbomachinery
Depositing User: Unnamed user with email sms67@cam.ac.uk
Date Deposited: 01 Nov 2018 01:53
Last Modified: 09 Sep 2021 02:35
DOI: 10.2514/1.J057057