Numerical investigation of low-noise airfoils inspired by the down coat of owls

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dc.contributor.author Bodling, Andrew
dc.contributor.author Sharma, Anupam
dc.contributor.author Sharma, Anupam
dc.contributor.department Aerospace Engineering
dc.date 2019-11-18T16:36:18.000
dc.date.accessioned 2020-06-29T22:45:39Z
dc.date.available 2020-06-29T22:45:39Z
dc.date.copyright Mon Jan 01 00:00:00 UTC 2018
dc.date.embargo 2019-12-06
dc.date.issued 2018-12-06
dc.description.abstract <p>Numerical analysis of airfoil geometries inspired by the down coat of the night owl is presented. The bioinspired geometry consists of an array of 'finlet fences', which is placed near the trailing edge of the baseline (NACA 0012) airfoil. Two fences with maximum nondimensional heights, H/delta* = 1 and 2.26 are investigated, where delta* is the displacement thickness at 2.9% chord upstream of the airfoil trailing edge. Wall-resolved large eddy simulations are performed at chord-based Reynolds number, Re-c = 5 x 10(5), flow Mach number, M = 0.2, and angle of attack, alpha = 0 degrees. The simulation results show significant reductions in unsteady surface pressure and farfield radiated noise with the fences, in agreement with the measurements available in the literature. Analysis of the results reveals that the fences increase the distance between the boundary layer turbulence (source) and the airfoil trailing (scattering) edge, which is identified to be the mechanism behind high-frequency noise reduction. These reductions are larger for the taller fence as the source-scattering edge separation is greater. Two-point correlations show that the fences reduce the spanwise coherence at low frequencies for separation distances greater than a fence pitch (distance between two adjacent fences) and increase the coherence for smaller distances, the increase being higher for the taller fence. This increase in coherence and the reduced obliqueness of the leading edge of the fence are hypothesized to be responsible for the small increase in farfield noise at low frequencies observed in the simulations with the taller fence.</p>
dc.description.comments <p>This is a peer-reviewed, un-copyedited version of an article accepted for publication/published in <em>Bioinspiration & Biomimetics</em>. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at DOI: <a href="http://dx.doi.org/10.1088/1748-3190/aaf19c" target="_blank">10.1088/1748-3190/aaf19c</a>. Posted with permission.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/aere_pubs/154/
dc.identifier.articleid 1157
dc.identifier.contextkey 15810203
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath aere_pubs/154
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/2000
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/aere_pubs/154/2018_AnupamSharma_NumericalInvestigationLowNoise.pdf|||Fri Jan 14 20:40:35 UTC 2022
dc.source.uri 10.1088/1748-3190/aaf19c
dc.subject.disciplines Aerospace Engineering
dc.subject.keywords large eddy simulations
dc.subject.keywords low noise airfoils
dc.subject.keywords night owl
dc.title Numerical investigation of low-noise airfoils inspired by the down coat of owls
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication 9797e35d-08ee-41c7-8982-c83e6db2ed8e
relation.isOrgUnitOfPublication 047b23ca-7bd7-4194-b084-c4181d33d95d
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