Journal article
On regime C flow around an oscillating circularcylinder
Journal of Fluid Mechanics, Vol.849, pp.968-1008
26/06/2018
Metrics
28 Record Views
UN Sustainable Development Goals (SDGs)
This output has contributed to the advancement of the following goals:
Source: InCites
Abstract
This paper focuses on the characteristics of the regime C flow (Tatsuno & Bearman, J. Fluid Mech., vol. 211, 1990, pp. 157-182) around an oscillating circular cylinder in still water. The regime C flow is characterised by the formation of large-scale vortex cores arranged as opposed von Karman vortex streets, resulting from a regular switching of vortex shedding directions with respect to the axis of oscillation. Both Floquet analysis and direct numerical simulations (DNS) are performed to investigate the two- (2-D) and three-dimensional (3-D) instabilities. The present study reveals that the low-wavenumber 3-D instability can emerge slightly before the 2-D instability in regime C. In total, five spanwise vortex modes were identified: (i) standing-wave pattern, S-mode; (ii) travelling-wave pattern, T-mode; (iii) mixed ST-mode; (iv) X-type vortex pattern, X-mode; and (v) U-type vortex pattern, U-mode. The modal analysis conducted in this study demonstrates that the vortex patterns and the corresponding spatial and temporal modulations of the dynamic loads of the S-, T- and mixed ST-modes are mainly induced by the 3-D instability of a single wavenumber. The characteristics of the X-mode are due to the superposition of the 3-D instabilities of multiple wavenumbers. The U-mode is dominated by a 2-D instability and its interaction with 3-D instabilities. The domain size dependence study demonstrates that the regime C flow is very sensitive to the spanwise length of the computational domain. The subcritical nature of the regime C flow is responsible for the discrepancy in the marginal stability curves obtained by independent Floquet stability analysis, DNS and physical experiments.
Details
- Title
- On regime C flow around an oscillating circularcylinder
- Creators
- Chengwang Xiong - University of Western AustraliaLiang Cheng - University of Western AustraliaFeifei Tong - University of Western AustraliaHongwei An - University of Western Australia
- Publication Details
- Journal of Fluid Mechanics, Vol.849, pp.968-1008
- Publisher
- Cambridge Univ Press
- Number of pages
- 41
- Grant note
- Australian Government; CGIAR DE150100428 / Australian Research Council through DECRA Schemes; Australian Research Council 2016YFE0200100 / National Key R&D Program of China University of Western Australia for the SIRF Scholarship Government of Western Australia
- Identifiers
- 991013041311502368
- Academic Unit
- Faculty of Science and Engineering
- Language
- English
- Resource Type
- Journal article