Please use this identifier to cite or link to this item: http://bura.brunel.ac.uk/handle/2438/31370
Title: On the slit trailing edges for aerofoil self-noise reduction
Authors: Woodhead, P
Chong, TP
Joseph, P
Wissink, J
Chaitanya, P
Keywords: aeroacoustics;noise control;flow control
Issue Date: 21-Jul-2025
Publisher: Cambridge University Press
Citation: Woodhead, P. et al. (2025) 'On the slit trailing edges for aerofoil self-noise reduction', Journal of Fluid Mechanics, 1015, A43, pp. 1 - 31. doi: 10.1017/jfm.2025.10370.
Abstract: This paper presents an experimental and analytical investigation into the use of trailing edge slits for the reduction of aerofoil trailing edge noise. The noise reduction mechanism is shown to be fundamentally different from conventional trailing edge serrations, relying on destructive interference from highly compact and coherent sources generated at either ends of the slit. This novel approach is the first to exploit the coherence intrinsic to the boundary layer turbulence. Furthermore, the study demonstrates that trailing edge slits not only achieve superior noise reductions compared with sawtooth serrations of the same amplitude at certain conditions, but also offer frequency-tuning capability for noise reduction. Noise reduction is driven by the destructive interference between acoustic sources at the root and tip of the slit, which radiate with a phase difference determined by the difference in times taken for the boundary layer flow to convect between the root and tip. Maximum noise reductions occur at frequencies where the phase difference between these sources is 180°. The paper also presents a detailed parametric study into the variation in noise reductions due to the slit length, slit wavelength and slit root width. Additionally, a simple two-source analytic model is proposed to explain the observed results. Wind tunnel measurements of the unsteady flow field around the trailing edge slits are also presented, providing insights into the underlying flow physics.
URI: https://bura.brunel.ac.uk/handle/2438/31370
DOI: https://doi.org/10.1017/jfm.2025.10370
ISSN: 0022-1120
Other Identifiers: ORCiD: Philip Woodhead https://orcid.org/0000-0002-8116-858X
ORCiD: Tze Pei Chong https://orcid.org/0000-0002-5272-3943
ORCiD: Jan Wissink https://orcid.org/0000-0002-3608-7449
ORCiD: Paruchuri Chaitanya https://orcid.org/0000-0001-5410-4006
Article number: A43
Appears in Collections:Dept of Mechanical and Aerospace Engineering Research Papers

Files in This Item:
File Description SizeFormat 
FullText.pdfCopyright © The Author(s), 2025. Published by Cambridge University Press. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.1.77 MBAdobe PDFView/Open


This item is licensed under a Creative Commons License Creative Commons