Print Email Facebook Twitter Internal shear layer and vortex shedding development of a structured porous coated cylinder using tomographic particle image velocimetry Title Internal shear layer and vortex shedding development of a structured porous coated cylinder using tomographic particle image velocimetry Author Arcondoulis, E.J.G. (University of Bristol) Liu, Y. (Southern University of Science and Technology) Ragni, D. (TU Delft Wind Energy) Avallone, F. (TU Delft Wind Energy) Rubio Carpio, A. (TU Delft Wind Energy) Sedaghatizadeh, N. (University of Adelaide) Yang, Y. (Southern University of Science and Technology) Li, Z. (Southern University of Science and Technology) Date 2023 Abstract 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 and, 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. To reference this document use: http://resolver.tudelft.nl/uuid:3489ec77-08da-4ced-a81e-2388034aee5e DOI https://doi.org/10.1017/jfm.2023.473 ISSN 0022-1120 Source Journal of Fluid Mechanics, 967 Part of collection Institutional Repository Document type journal article Rights © 2023 E.J.G. Arcondoulis, Y. Liu, D. Ragni, F. Avallone, A. Rubio Carpio, N. Sedaghatizadeh, Y. Yang, Z. Li Files PDF internal_shear_layer_and_ ... imetry.pdf 3.87 MB Close viewer /islandora/object/uuid:3489ec77-08da-4ced-a81e-2388034aee5e/datastream/OBJ/view