Experimental near-field analysis for flow induced noise of a structured porous-coated cylinder

Maryami, Reza; Arcondoulis, Elias; Liu, Qian; Liu, Yu

doi:10.1016/j.jsv.2023.117611

Cited by 27 publications

(60 citation statements)

References 54 publications

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“…Xia et al (2018) observed that the velocity fluctuations in the wake shifted by 9 % towards lower frequency (relative to a solid cylinder), due to the widening of the wake region. A Strouhal number decrease in the far-field noise signal (relative to a solid cylinder with the same diameter as the PCC inner diameter) has been shown by both high-fidelity numerical simulations (Liu et al 2012) and experiments (Geyer & Sarradj 2016;Arcondoulis et al 2019;Zamponi et al 2022;Maryami et al 2023) for different porosities and t/d ratios. Conversely, a Strouhal number increase of lift fluctuations at the vortex shedding frequency is observed when compared with a solid cylinder with the same diameter as the PCC outer diameter (Naito & Fukagata 2012).…”

Section: Introductionmentioning

confidence: 84%

“…2022; Maryami et al. 2023) for different porosities and ratios. Conversely, a Strouhal number increase of lift fluctuations at the vortex shedding frequency is observed when compared with a solid cylinder with the same diameter as the PCC outer diameter (Naito & Fukagata 2012).…”

Section: Introductionmentioning

confidence: 99%

“…The SPCC in recent years has gained some prominence for its passive flow and noise control capability. Surface pressure fluctuations of an SPCC were recorded by Maryami et al (2023) who used remote pressure sensing to observe the fluctuating lift and drag components at the outer diameter and explained the coherence between fluctuating pressures at various circumferential stations. An identical SPCC design has been applied to the leeward side of a cylinder for passive and active flow control (Yu et al 2021;Xu et al 2022b) and similar square-shaped pore designs have been used for drag reduction purposes (Farrell, Gibbons & Persoons 2022).…”

Section: Introductionmentioning

confidence: 99%

“…Surface pressure fluctuations of an SPCC were recorded by Maryami et al. (2023) who used remote pressure sensing to observe the fluctuating lift and drag components at the outer diameter and explained the coherence between fluctuating pressures at various circumferential stations. An identical SPCC design has been applied to the leeward side of a cylinder for passive and active flow control (Yu et al.…”

Section: Introductionmentioning

confidence: 99%

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Internal shear layer and vortex shedding development of a structured porous coated cylinder using tomographic particle image velocimetry

et al. 2023

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Vortex shedding in the wake of a cylinder in uniform flow can be suppressed via the application of a porous coating; however, the suppression mechanism is not fully understood. The internal flow field of a porous coated cylinder (PCC) can provide a deeper understanding of how the flow within the porous medium affects the wake development. A structured PCC (SPCC) was three-dimensionally printed using a transparent material and tested in water tunnel facilities using flow visualisation and tomographic particle image velocimetry at outer-diameter Reynolds numbers of $Re = 7 \times 10^{3}$ and $7.3 \times 10^{4}$ , respectively. The internal and near-wall flow fields are analysed at the windward and mid-circumference regions. Flow stagnation is observed in the porous layer on the windward side and its boundary is shown to fluctuate with time in the outermost porous layer. This stagnation region generates a quasi-aerodynamic body that influences boundary layer development on the SPCC inner diameter, that separates into a shear layer within the porous medium. For the first time via experiment, spectral content within the separated shear layer reveals vortex shedding processes emanating through single pores at the outer diameter, providing strong evidence that SPCC vortex shedding originates from the inner diameter. Velocity fluctuations linked to this vortex shedding propagate through the porous layers into the external flow field at a velocity less than that of the free stream. The Strouhal number linked to this velocity accurately predicts the SPCC vortex shedding frequency.

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Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Internal shear layer and vortex shedding development of a structured porous coated cylinder using tomographic particle image velocimetry

et al. 2023

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“…The pressure taps are comprised of a brass tube with inner and outer diameters of 0.8 mm and 1.6 mm, respectively, fitted in a designated housing on the solid-layer surface. As shown in figure 4(a), the brass tubes were connected to the remote-sensing probes using brass and flexible polyurethane tubing with inner and outer diameters of 0.8 and 4 mm, respectively, similar to that used by Maryami et al (2023c). Each remote probe consists of a microphone holder and a Panasonic WM-61A microphone with a circular sensing diameter of 2 mm attached to a pinhole with a diameter of 0.4 mm (see figure 4b).…”

Section: Chamber Designmentioning

confidence: 99%

Flow and aerodynamic noise control of a circular cylinder by local blowing

Maryami,

Arcondoulis,

Liu

2024

J. Fluid Mech.

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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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Comparative experimental studies on flow and noise of cylinder affected by coated and downstream metal foams

Xu,

Du,

Mao

et al. 2024

Aerospace Science and Technology

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Experimental near-field analysis for flow induced noise of a structured porous-coated cylinder

Cited by 27 publications

References 54 publications

Internal shear layer and vortex shedding development of a structured porous coated cylinder using tomographic particle image velocimetry

Internal shear layer and vortex shedding development of a structured porous coated cylinder using tomographic particle image velocimetry

Flow and aerodynamic noise control of a circular cylinder by local blowing

Comparative experimental studies on flow and noise of cylinder affected by coated and downstream metal foams

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