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Viscous oscillatory flow around a circular cylinder at low Keulegan–Carpenter numbers and frequency parameters
Author(s) -
Iliadis G.,
Anagnostopoulos P.
Publication year - 1998
Publication title -
international journal for numerical methods in fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 112
eISSN - 1097-0363
pISSN - 0271-2091
DOI - 10.1002/(sici)1097-0363(19980228)26:4<403::aid-fld640>3.0.co;2-v
Subject(s) - vortex shedding , potential flow around a circular cylinder , flow (mathematics) , mechanics , vorticity , mathematics , cylinder , vortex , kármán vortex street , physics , reynolds number , geometry , turbulence , open channel flow
The results of a numerical study of the viscous oscillating flow around a circular cylinder at low Keulegan–Carpenter numbers ( KC ) and frequency parameters (β) are presented in this paper. The finite element method was used for the solution of the Navier–Stokes equations in the formulation where the streamfunction and vorticity are the field variables. The computation was conducted at Keulegan–Carpenter numbers extending up to KC =15 and frequency parameters ranging between β=6 and 100. At low values of the Keulegan–Carpenter number the flow remains symmetrical. As the Keulegan–Carpenter number is increased over a certain value which depends also on the frequency parameter, asymmetries appear in the flow which are eventually amplified and lead finally to complex vortex‐shedding patterns, some of which are markedly different from those observed at higher frequency parameters. The solution revealed that although for certain values of KC and β the shedding of vortices is periodic, there also exists a complicated flow regime in which the flow is not periodic but switches between different modes in consecutive cycles of flow oscillation. For the various flow cases examined, the traces of the hydrodynamic forces are presented and the hydrodynamic coefficients and RMS values of the in‐line force are compared with experimental evidence. © 1998 John Wiley & Sons, Ltd.