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Prediction of Porous Trailing Edge Noise Reduction via Acoustic Perturbation Equations and Volume Averaging

Faßmann, Benjamin and Rautmann, Christof and Ewert, Roland and Delfs, Jan Werner (2015) Prediction of Porous Trailing Edge Noise Reduction via Acoustic Perturbation Equations and Volume Averaging. In: 21st AIAA/CEAS Aeroacoustics Conference, 2 (2525), pp. 1166-1183. 21th AIAA/CEAS Aeroacoustics Conference, 22.-26. Juni 2015, Dallas, Texas. DOI: 10.2514/6.2015-2525) ISBN 978-1-5108-0820-1

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Official URL: http://arc.aiaa.org/doi/abs/10.2514/6.2015-2525

Abstract

Edge noise is generated if turbulence interacts with solid edges. Reduction of trailing edge noise of airfoils can be achieved by replacing the solid material at the trailing edge by inlays of porous permeable material. The acoustic benefit of approximately 6 dB of such treatment is known from experiments. Enroute to numerically optimized porous properties, this paper presents a first principle based Computational Aeroacoustics (CAA) method for predicting the acoustic effect of a porous NACA0012 trailing edge. In a hybrid two-step CFD/CAA procedure the turbulence statistics from a solution of the Volume Averaged Navier-Stokes (VANS) equations is used as a basis for the prediction of turbulent-boundary-layer trailing-edge noise (TBL-TEN). For the acoustic part of the calculation, the Acoustic Perturbation Equations (APE) are solved in the flow field. Inside the porous regions, a different set of governing equations, referred to as Linear Perturbation Equations (LPE) will be solved. The LPE represent a modified form of the Linearized Euler Equations (LEE) with the APE vorticity source term shifted to the right-hand side. The new set of equations is derived by volume averaging the Navier-Stokes equations and decomposing the flow variables into a time-averaged mean part and a fluctuating part and isolating the vorticity source term to the right-hand side of the momentum equation. The LPE are verified by an analytical solution. The simulation results of a NACA0012 airfoil geometry with and without porous trailing edge treatment are compared to wind tunnel measurements. The noise reduction effect of such a trailing edge treatment is successfully demonstrated.

Item URL in elib:https://elib.dlr.de/100338/
Document Type:Conference or Workshop Item (Speech)
Additional Information:AIAA Paper 2015-2525
Title:Prediction of Porous Trailing Edge Noise Reduction via Acoustic Perturbation Equations and Volume Averaging
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Faßmann, Benjaminbenjamin.fassmann (at) dlr.deUNSPECIFIED
Rautmann, Christofchristof.rautmann (at) dlr.deUNSPECIFIED
Ewert, Rolandroland.ewert (at) dlr.deUNSPECIFIED
Delfs, Jan Wernerjan.delfs (at) dlr.deUNSPECIFIED
Date:June 2015
Journal or Publication Title:21st AIAA/CEAS Aeroacoustics Conference
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Volume:2
DOI :10.2514/6.2015-2525)
Page Range:pp. 1166-1183
Series Name:Conference Proceedings
ISBN:978-1-5108-0820-1
Status:Published
Keywords:Hinterkantenschall; Porosität; Simulation; Volumen-Mittelung;
Event Title:21th AIAA/CEAS Aeroacoustics Conference
Event Location:Dallas, Texas
Event Type:international Conference
Event Dates:22.-26. Juni 2015
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 - Simulation and Validation
Location: Braunschweig
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Technical Acoustics
Deposited By: Faßmann, Benjamin
Deposited On:10 Dec 2015 14:16
Last Modified:31 Jul 2019 19:57

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