Data-driven determination of low-frequency dipole noise mechanisms in stalled airfoils
Data-driven determination of low-frequency dipole noise mechanisms in stalled airfoils
An aeroacoustic investigation of planar time-resolved particle image velocimetry (PIV) measurements in the streamwise surface-normal plane of a NACA 0012 airfoil in static stall is presented at chord-based Reynolds number Rec=7.1×104
. Instantaneous planar pressure reconstructions are obtained using a Poisson solver and the dipole noise emanating from the surface is extrapolated via Curle’s acoustic analogy. To correlate structure in the velocity field to the generation of noise, a data-driven framework utilising the proper orthogonal decomposition (POD) and the spectral Linear Stochastic Estimation (sLSE) is employed. The flow structures responsible for noise are found to concentrate in proximity to the trailing edge. In addition, a conditional analysis for the extreme noise events reveals that downwash and upwash events in proximity to the trailing edge, coupled with slow and fast-moving fluid at the incipient shear layer, are correlated to local maxima and minima in the acoustic fluctuations, respectively.
Carter, Douglas
75fd127b-b918-4bd3-9ada-6e1c7e1ad69d
Ganapathisubramani, Bharathram
5e69099f-2f39-4fdd-8a85-3ac906827052
11 February 2023
Carter, Douglas
75fd127b-b918-4bd3-9ada-6e1c7e1ad69d
Ganapathisubramani, Bharathram
5e69099f-2f39-4fdd-8a85-3ac906827052
Carter, Douglas and Ganapathisubramani, Bharathram
(2023)
Data-driven determination of low-frequency dipole noise mechanisms in stalled airfoils.
Experiments in Fluids, 64.
Abstract
An aeroacoustic investigation of planar time-resolved particle image velocimetry (PIV) measurements in the streamwise surface-normal plane of a NACA 0012 airfoil in static stall is presented at chord-based Reynolds number Rec=7.1×104
. Instantaneous planar pressure reconstructions are obtained using a Poisson solver and the dipole noise emanating from the surface is extrapolated via Curle’s acoustic analogy. To correlate structure in the velocity field to the generation of noise, a data-driven framework utilising the proper orthogonal decomposition (POD) and the spectral Linear Stochastic Estimation (sLSE) is employed. The flow structures responsible for noise are found to concentrate in proximity to the trailing edge. In addition, a conditional analysis for the extreme noise events reveals that downwash and upwash events in proximity to the trailing edge, coupled with slow and fast-moving fluid at the incipient shear layer, are correlated to local maxima and minima in the acoustic fluctuations, respectively.
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ExiF__Noise_Generation_of_Stalled_Aerofoils__Accepted_ (2)
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Accepted/In Press date: 9 January 2023
Published date: 11 February 2023
Identifiers
Local EPrints ID: 474333
URI: http://eprints.soton.ac.uk/id/eprint/474333
ISSN: 0723-4864
PURE UUID: 0974b001-179d-42b0-b24d-704755c1f97b
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Date deposited: 20 Feb 2023 17:47
Last modified: 17 Mar 2024 03:22
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Author:
Douglas Carter
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