Numerical analysis of noise reduction mechanisms of serrated trailing edges under zero lift condition

Wouter van der Velden, Francesco Avallone, Daniele Ragni

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

11 Citations (Scopus)
75 Downloads (Pure)

Abstract

The relation between the far-field noise and the flow field, in presence of serrated and combed-serrated trailing edge, is studied to explain the associated noise reduction mechanisms. Both serration geometries are retrofitted to a NACA 0018 wing. Computations are carried out by solving the fully explicit, transient, compressible Lattice Boltzmann equation , while the acoustic far-field is obtained by means of the Ffowcs-Williams and Hawking integral solution. A link between the far-field noise and the relevant flow parameters that contribute to noise generation is proposed. It is confirmed that the intensity of the surface pressure fluctuations varies in the streamwise direction, and that most of the low-frequency noise is generated at the root of the serrations. It is concluded that the additional noise reduction achieved by the use of combs is due to the mitigation of the outward flow motion at the root. Furthermore, it is shown that the edge-oriented correlation length and the convection velocity of the surface pressure fluctuations are the two statistical flow parameters that influence both the intensity and the frequency range of noise reduction. It is found that a larger edge-oriented correlation length contributes to noise reduction, by generating destructive interference between the pressure waves scattered along the slanted edge.
Original languageEnglish
Title of host publication23rd AIAA/CEAS Aeroacoustics Conference
Subtitle of host publication5-9 June 2017, Denver, Colorado
PublisherAmerican Institute of Aeronautics and Astronautics Inc. (AIAA)
Number of pages15
ISBN (Electronic)978-1-62410-504-3
DOIs
Publication statusPublished - 2017
Event23rd AIAA/CEAS Aeroacoustics Conference - Denver, United States
Duration: 5 Jun 20179 Jun 2017
Conference number: 23
https://doi.org/10.2514/MAA17

Conference

Conference23rd AIAA/CEAS Aeroacoustics Conference
CountryUnited States
CityDenver
Period5/06/179/06/17
Internet address

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