High-order computations on aerofoil-gust interaction noise
and the effects of wavy leading edges
High-order computations on aerofoil-gust interaction noise
and the effects of wavy leading edges
High-order accurate numerical simulations are performed to investigate the effects of wavy leading edges on aerofoil gust interaction (AGI) noise. The present study is based on periodic velocity dis-turbances predominantly in streamwise (x-) and vertical (y-) directions that are mainly responsible for the surface pressure fluctuation of an aerofoil. The perturbed velocity components of the present gust model do not vary in the spanwise (z-) direction. In general, the present results show that wavy leading edges lead to reduced AGI noise. Under the current incident gusts, it is found that the ratio of the wavy leading-edge peak-to-peak amplitude (LEA) to the longitudinal wavelength of the incident gust (?g) is the most important factor for the reduction of AGI noise. It is observed that AGI noise reduces with increasing LEA/?g, and significant noise reduction can be achieved for LEA/?g?0.3. The present results also suggest that any two different cases with the same LEA/?g lead to a strong similarity in their profiles of noise reduction relative to the straight leading-edge case. The wavelength of wavy leading edges (LEW), however, shows minor influence on the reduction of AGI noise under the present gust profiles used. Nevertheless, the present results show that a meaningful improvement in noise reduction may be achieved when 1.06LEW/?g 61.5. In addition, it is found that the beneficial effects of wavy leading edges are maintained for various angles of attack and aerofoil thicknesses. Also, wavy leading edges remain effective in reducing AGI noise for gust profiles containing multiple frequency components. It is discovered in the current research that wavy leading edges result in in-coherent response time to the incident gust across the span, which causes a decreased level of surface pressure fluctuations, hence a reduced level of AGI noise.
Lau, Alex Siu Hong
017b1dac-0524-4474-8d86-5172262cbfb0
1 October 2012
Lau, Alex Siu Hong
017b1dac-0524-4474-8d86-5172262cbfb0
Kim, J.W.
fedabfc6-312c-40fd-b0c1-7b4a3ca80987
Lau, Alex Siu Hong
(2012)
High-order computations on aerofoil-gust interaction noise
and the effects of wavy leading edges.
University of Southampton, Faculty of Engineering and the Environment, Doctoral Thesis, 133pp.
Record type:
Thesis
(Doctoral)
Abstract
High-order accurate numerical simulations are performed to investigate the effects of wavy leading edges on aerofoil gust interaction (AGI) noise. The present study is based on periodic velocity dis-turbances predominantly in streamwise (x-) and vertical (y-) directions that are mainly responsible for the surface pressure fluctuation of an aerofoil. The perturbed velocity components of the present gust model do not vary in the spanwise (z-) direction. In general, the present results show that wavy leading edges lead to reduced AGI noise. Under the current incident gusts, it is found that the ratio of the wavy leading-edge peak-to-peak amplitude (LEA) to the longitudinal wavelength of the incident gust (?g) is the most important factor for the reduction of AGI noise. It is observed that AGI noise reduces with increasing LEA/?g, and significant noise reduction can be achieved for LEA/?g?0.3. The present results also suggest that any two different cases with the same LEA/?g lead to a strong similarity in their profiles of noise reduction relative to the straight leading-edge case. The wavelength of wavy leading edges (LEW), however, shows minor influence on the reduction of AGI noise under the present gust profiles used. Nevertheless, the present results show that a meaningful improvement in noise reduction may be achieved when 1.06LEW/?g 61.5. In addition, it is found that the beneficial effects of wavy leading edges are maintained for various angles of attack and aerofoil thicknesses. Also, wavy leading edges remain effective in reducing AGI noise for gust profiles containing multiple frequency components. It is discovered in the current research that wavy leading edges result in in-coherent response time to the incident gust across the span, which causes a decreased level of surface pressure fluctuations, hence a reduced level of AGI noise.
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Alex_Lau_Final_PhD_Thesis.pdf
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Published date: 1 October 2012
Organisations:
University of Southampton, Faculty of Engineering and the Environment
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Local EPrints ID: 355961
URI: http://eprints.soton.ac.uk/id/eprint/355961
PURE UUID: 2b57a440-c8b6-4f76-9ae7-a9ae136ad6b4
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Date deposited: 18 Nov 2013 14:34
Last modified: 15 Mar 2024 03:21
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Author:
Alex Siu Hong Lau
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