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Simulation of Cold Jet Installation Noise using a Stochastic Backscatter Model

Ewert, Roland and Dierke, Jürgen and Neifeld, Andrej (2017) Simulation of Cold Jet Installation Noise using a Stochastic Backscatter Model. In: 23rd AIAA/CEAS Aeroacoustics Conference, 2017. 23rd AIAA/CEAS Aeroacoustics Conference 5-9 June 2017, Denver, Colorado AIAA AVIATION Forum, 5.-9. Juni 2017, Denver, Colorado, USA. ISBN 978-162410504-3

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Abstract

This work presents results of Computational Aeroacoustics simulation for two different installation noise problems involving a cold jet interacting with a wing. Similar to very large-eddy simulation (VLES), the resolvable very large scales of turbulent fluctuations are directly calculated and the dissipation of the non-resolved scales is accounted for by a subfilter scale stress model. In addition, stochastic forcing in space and time is applied to model turbulent backscatter. The paper presents and discusses the rationale to explicitly realize turbulent backscatter along with details of the proposed stochastic backscatter model and its calibration. As a novel approach, the entire subfilter forcing function is modeled by means of an eddy-relaxation source term that provides forcing and dissipation as an entangled compound. The relaxation parameter defines the amount of correlation of the subfilter forcing with resolved quantities. Its proper calibration is achieved using decaying homogeneous isotropic turbulence. Further characteristics of the backscatter forcing are analyzed from synthetic turbulence data. The first jet-wing interaction problem studied is based on a generic static jet interacting with a non-inclined rectangular wing. The second problem deals with a dual-stream nozzle installed at a high-lift wing with deployed flap and slat in wind tunnel flow under approach conditions. For both problems installation noise from the airframe yields higher peak levels than the jet-noise contribution alone. For the first problem, relative to the corresponding jet spectrum a low-frequency narrow-band contribution is observed that can be attributed to coherent jet structures interacting with the airfoil trailing edge. Very good agreement with measured spectra is obtained. For the second problem a broadband airframe installation contribution to the overall spectrum is predicted with peak frequency above the jet contribution.

Item URL in elib:https://elib.dlr.de/125426/
Document Type:Conference or Workshop Item (Speech)
Title:Simulation of Cold Jet Installation Noise using a Stochastic Backscatter Model
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Ewert, Rolandroland.ewert (at) dlr.deUNSPECIFIED
Dierke, Jürgenjuergen.dierke (at) dlr.deUNSPECIFIED
Neifeld, Andrejandrej.neifeld (at) dlr.deUNSPECIFIED
Date:2017
Journal or Publication Title:23rd AIAA/CEAS Aeroacoustics Conference, 2017
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:No
Series Name:AIAA Paper 2017-3017
ISBN:978-162410504-3
Status:Published
Keywords:Jet-Flap Installation Noise, Stochastic Backscatter, LES, CAA, FRPM
Event Title:23rd AIAA/CEAS Aeroacoustics Conference 5-9 June 2017, Denver, Colorado AIAA AVIATION Forum
Event Location:Denver, Colorado, USA
Event Type:international Conference
Event Dates:5.-9. Juni 2017
Organizer:AIAA/CEAS
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:fixed-wing aircraft
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Flight Physics
Location: Braunschweig
Institutes and Institutions:Institute for Aerodynamics and Flow Technology > Technical Acoustics
Deposited By: Ewert, Dr.-Ing. Roland
Deposited On:03 Jan 2019 12:07
Last Modified:31 Jul 2019 20:23

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