Flow-induced noise from a seal-vibrissa-shaped cylinder
Flow-induced noise from a seal-vibrissa-shaped cylinder
Inspired by the special structure of seal vibrissae and their ability to effectively suppress vortex-induced vibrations, this paper studies the characteristics of flow and aerodynamic noise generated around a seal-vibrissa-shaped cylinder at a Reynolds number (based on the hydrodynamic diameter and freestream velocity) of 6 × 10
4 using the delayed detached-eddy simulation model combined with the acoustic analogy approach. The far-field aerodynamic noise has also been measured at Reynolds numbers of 6 × 10
4∼1.2 × 10
5 in an anechoic wind tunnel to compare the seal-vibrissa-shaped cylinder with cylindrical and elliptical bars of the same characteristic dimensions. The calculated spectra of aerodynamic noise agree well with the wind tunnel measurements, verifying the accuracy of the numerical simulations. It is found that the three-dimensional flow separations introduced by the alternative saddle and nodal planes of the seal-vibrissa-shaped cylinder inhibit shear layer interactions and reduce the spanwise coherence, resulting in a wake with no dominant coherent structures and thus suppressing pressure fluctuations on the solid surfaces. The configuration of seal-vibrissa-shaped cylinder eliminates the regular Kármán vortex street which generally occurs in a cylinder wake, and consequently inhibits the tonal peak in the aerodynamic noise. The sound pressure level is also reduced in most frequencies. The consistency of the normalized spectra of the far-field aerodynamic noise and the vortex shedding frequency at different inflow speeds demonstrates the high accuracy of the anechoic wind tunnel measurements. Compared with cylinders with circular or elliptical cross sections, the seal-vibrissa-shaped cylinder effectively reduces the flow-induced noise by, respectively, 13 dB or 11 dB for a far-field receiver of 90° at Reynolds number of 6 × 10
4, showing great potential in reducing aerodynamic noise.
Aerodynamic noise, Anechoic wind tunnel measurement, Flow behaviour, Noise control, Seal-vibrissa-shaped cylinder
Zhu, J.Y.
4fd6be3f-f28d-429c-96ec-f4498f109081
Yuan, Y.Y.
2ff05a07-803c-4ba3-9039-c2a7602a6a53
Hu, Zhiwei
dd985844-1e6b-44ba-9e1d-fa57c6c88d65
Yang, Z.G.
440f68b9-1fdd-40c4-a4c8-7849a2b51dfa
Xu, J.Q.
c8de1986-3517-411e-a74a-85b68e1e1251
3 February 2024
Zhu, J.Y.
4fd6be3f-f28d-429c-96ec-f4498f109081
Yuan, Y.Y.
2ff05a07-803c-4ba3-9039-c2a7602a6a53
Hu, Zhiwei
dd985844-1e6b-44ba-9e1d-fa57c6c88d65
Yang, Z.G.
440f68b9-1fdd-40c4-a4c8-7849a2b51dfa
Xu, J.Q.
c8de1986-3517-411e-a74a-85b68e1e1251
Zhu, J.Y., Yuan, Y.Y., Hu, Zhiwei, Yang, Z.G. and Xu, J.Q.
(2024)
Flow-induced noise from a seal-vibrissa-shaped cylinder.
Journal of Sound and Vibration, 570, [118135].
(doi:10.1016/j.jsv.2023.118135).
Abstract
Inspired by the special structure of seal vibrissae and their ability to effectively suppress vortex-induced vibrations, this paper studies the characteristics of flow and aerodynamic noise generated around a seal-vibrissa-shaped cylinder at a Reynolds number (based on the hydrodynamic diameter and freestream velocity) of 6 × 10
4 using the delayed detached-eddy simulation model combined with the acoustic analogy approach. The far-field aerodynamic noise has also been measured at Reynolds numbers of 6 × 10
4∼1.2 × 10
5 in an anechoic wind tunnel to compare the seal-vibrissa-shaped cylinder with cylindrical and elliptical bars of the same characteristic dimensions. The calculated spectra of aerodynamic noise agree well with the wind tunnel measurements, verifying the accuracy of the numerical simulations. It is found that the three-dimensional flow separations introduced by the alternative saddle and nodal planes of the seal-vibrissa-shaped cylinder inhibit shear layer interactions and reduce the spanwise coherence, resulting in a wake with no dominant coherent structures and thus suppressing pressure fluctuations on the solid surfaces. The configuration of seal-vibrissa-shaped cylinder eliminates the regular Kármán vortex street which generally occurs in a cylinder wake, and consequently inhibits the tonal peak in the aerodynamic noise. The sound pressure level is also reduced in most frequencies. The consistency of the normalized spectra of the far-field aerodynamic noise and the vortex shedding frequency at different inflow speeds demonstrates the high accuracy of the anechoic wind tunnel measurements. Compared with cylinders with circular or elliptical cross sections, the seal-vibrissa-shaped cylinder effectively reduces the flow-induced noise by, respectively, 13 dB or 11 dB for a far-field receiver of 90° at Reynolds number of 6 × 10
4, showing great potential in reducing aerodynamic noise.
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Flow-induced noise from a seal-vibrissa-shaped cylinder_Final
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Accepted/In Press date: 27 October 2023
e-pub ahead of print date: 28 October 2023
Published date: 3 February 2024
Additional Information:
Funding Information:
This work was supported by National Natural Science Foundation of China (51875411, 52232013). The supports from National Engineering Research Center of New Energy Vehicles and Power Systems as well as Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management Systems are appreciated. The numerical simulations were performed on the Iridis5 cluster managed by the University of Southampton.
Funding Information:
This work was supported by National Natural Science Foundation of China ( 51875411 , 52232013 ). The supports from National Engineering Research Center of New Energy Vehicles and Power Systems as well as Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management Systems are appreciated. The numerical simulations were performed on the Iridis5 cluster managed by the University of Southampton.
Publisher Copyright:
© 2023
Keywords:
Aerodynamic noise, Anechoic wind tunnel measurement, Flow behaviour, Noise control, Seal-vibrissa-shaped cylinder
Identifiers
Local EPrints ID: 485723
URI: http://eprints.soton.ac.uk/id/eprint/485723
ISSN: 0022-460X
PURE UUID: 0eba67ec-ed22-4868-add6-e167e68e743c
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Date deposited: 15 Dec 2023 17:38
Last modified: 14 Jun 2024 16:42
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Contributors
Author:
J.Y. Zhu
Author:
Y.Y. Yuan
Author:
Z.G. Yang
Author:
J.Q. Xu
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