Effect of a porous coating on the vortex shedding noise of a cylinder in turbulent flow

Geyer, Thomas

doi:10.1016/j.apacoust.2022.108834

Cited by 7 publications

(2 citation statements)

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“…Porous coated cylinders effective in vortex shedding suppression typically possess similar properties. These properties include the numbers of pores per inch (PPI) (Sueki et al 2009(Sueki et al , 2010, the porosity (Arcondoulis et al 2019;Li et al 2020b; and airflow resistivity (Geyer 2020(Geyer , 2022aSharma, Geyer & Arcondoulis 2023). The typical PPI range of common randomised porous media (such as metal foam or porous polyurethane) is from 5 to 30 PPI (Sueki et al 2009(Sueki et al , 2010Ruck, Klausmann & Wacker 2011;Aguiar, Yao & Liu 2016), with significant vortex shedding tone reduction observed using materials of 10 PPI or lower (Ruck et al 2011;Aguiar et al 2016;Arcondoulis et al 2021b;Wen et al 2021).…”

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: 99%

“…2020 b ; Zhang et al. 2020) and airflow resistivity (Geyer 2020, 2022 a ; Sharma, Geyer & Arcondoulis 2023). The typical PPI range of common randomised porous media (such as metal foam or porous polyurethane) is from 5 to 30 PPI (Sueki et al.…”

Section: Introductionmentioning

confidence: 99%