Characteristic spanwise length scales of streamwise vortical structures in the wake of a circular cylinder at Re = 1500 measured via global and local approaches
Wake characteristics of the flow past a circular cylinder are analysed in detail at Reynolds number Re = 1500 via direct numerical simulation. A periodic spanwise domain of length 1.5pD has been found to yield correct first- and second-order wake statistics in remarkable agreement with published res...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/382915 |
| Acceso en línea: | https://hdl.handle.net/2117/382915 https://dx.doi.org/10.1016/j.compfluid.2022.105760 |
| Access Level: | acceso abierto |
| Palabra clave: | Fluid mechanics Fluid dynamics Cylinders Direct numerical simulation Incompressible flow Cylinder wake instability Hilberttransform Autocorrelation Aerodynamic forces Mecànica de fluids Dinàmica de fluids Cilindres Àrees temàtiques de la UPC::Enginyeria mecànica::Mecànica de fluids |
| Sumario: | Wake characteristics of the flow past a circular cylinder are analysed in detail at Reynolds number Re = 1500 via direct numerical simulation. A periodic spanwise domain of length 1.5pD has been found to yield correct first- and second-order wake statistics in remarkable agreement with published results at the same and closeby Re. A KelvinHelmholtz instability with a frequency fKH ¿ 0.666 is observed to occur intermittently in the shear layers issued from the top and bottom of the cylinder. The three-dimensional patterns in the wake have an estimated spanwise length scale l1 z/D ¿ 0.70 (D is the cylinder diameter) in the near-wake at (x,y)/D = (3,0.5), downstream from the cylinder, when quantified by autocorrelation (global approach). When using the Hilbert-transform (local approach) instead, the predicted length scale of streamwise vortical structures is distributed around ¿z/D ¿ 0.33 at the same sampling location. Our results show that the two approaches measure different aspects of three-dimensionality: while the former informs of the typical spanwise spacing of streamwise vortices, the latter quantifies the local spanwise size of these same flow structures |
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