Flow and aerodynamic noise control of a circular cylinder by local blowing
Flow and aerodynamic noise control of a circular cylinder by local blowing
In this experimental study, the impact of symmetric local blowing on suppressing the vortex-induced noise of a circular cylinder was investigated. A highly instrumented cylinder with pressure taps and a series of blowing chambers was used to inject air along the span (seven times the cylinder diameter) at circumferential angles \theta _{b}={\pm }41^{\circ }, {\pm }90^{\circ } and {\pm }131^{\circ } corresponding to the boundary layer, shear layers on the cylinder and separated shear layers, respectively. The investigation aimed to understand the noise reduction mechanism of local blowing by conducting near-field pressure and far-field noise measurements in synchronisation with flow field velocity measurements. Near-field pressure was measured around the circumference of the cylinder using a remote-sensing technique and planar particle image velocimetry was implemented to measure the velocity of the wake flow field at a diameter-based Reynolds number of Re=7\times 10^{4}. The results revealed that the interaction of the rolling up separated shear layers, under the influence of high-momentum fluid travelling from the free stream to the wake, induced significant vertical flow movement in the vortex-formation region. This movement led to strong alternating surface pressure fluctuations at the cylinder's shoulders, contributing to the scattering of noise. It was demonstrated that local blowing delayed vortex shedding for all cases, except at \theta _{b}={\pm }90^{\circ }, which elongated the shear layers and pushed the high-momentum transfer area farther downstream. The application of local blowing at \theta _{b}={\pm }41^{\circ } was particularly effective in increasing the vortex formation size due to reduced entrainment of fluid-bearing vorticity.
Maryami, Reza
48476c94-c0fe-4743-b55c-2c63d83bbb8d
Arcondoulis, Elias J.G.
4e0c8bdf-1810-4d4e-b8e8-9ba9ccd6b746
Liu, Yu
e706e388-6bf7-4db5-ace6-6e477da056d4
10 February 2024
Maryami, Reza
48476c94-c0fe-4743-b55c-2c63d83bbb8d
Arcondoulis, Elias J.G.
4e0c8bdf-1810-4d4e-b8e8-9ba9ccd6b746
Liu, Yu
e706e388-6bf7-4db5-ace6-6e477da056d4
Maryami, Reza, Arcondoulis, Elias J.G. and Liu, Yu
(2024)
Flow and aerodynamic noise control of a circular cylinder by local blowing.
Journal of Fluid Mechanics, 980, [A56].
(doi:10.1017/jfm.2024.39).
Abstract
In this experimental study, the impact of symmetric local blowing on suppressing the vortex-induced noise of a circular cylinder was investigated. A highly instrumented cylinder with pressure taps and a series of blowing chambers was used to inject air along the span (seven times the cylinder diameter) at circumferential angles \theta _{b}={\pm }41^{\circ }, {\pm }90^{\circ } and {\pm }131^{\circ } corresponding to the boundary layer, shear layers on the cylinder and separated shear layers, respectively. The investigation aimed to understand the noise reduction mechanism of local blowing by conducting near-field pressure and far-field noise measurements in synchronisation with flow field velocity measurements. Near-field pressure was measured around the circumference of the cylinder using a remote-sensing technique and planar particle image velocimetry was implemented to measure the velocity of the wake flow field at a diameter-based Reynolds number of Re=7\times 10^{4}. The results revealed that the interaction of the rolling up separated shear layers, under the influence of high-momentum fluid travelling from the free stream to the wake, induced significant vertical flow movement in the vortex-formation region. This movement led to strong alternating surface pressure fluctuations at the cylinder's shoulders, contributing to the scattering of noise. It was demonstrated that local blowing delayed vortex shedding for all cases, except at \theta _{b}={\pm }90^{\circ }, which elongated the shear layers and pushed the high-momentum transfer area farther downstream. The application of local blowing at \theta _{b}={\pm }41^{\circ } was particularly effective in increasing the vortex formation size due to reduced entrainment of fluid-bearing vorticity.
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Published date: 10 February 2024
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Local EPrints ID: 506129
URI: http://eprints.soton.ac.uk/id/eprint/506129
ISSN: 0022-1120
PURE UUID: 74122f75-006c-4b69-b922-0aee563e2fb9
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Date deposited: 28 Oct 2025 18:34
Last modified: 29 Oct 2025 03:15
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Author:
Reza Maryami
Author:
Elias J.G. Arcondoulis
Author:
Yu Liu
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