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Modification of three-dimensional transition in the wake of a rotationally oscillating cylinder

Lo Jacono, David and Leontini, Justin S. and Thompson, Mark C. and Sheridan, John Modification of three-dimensional transition in the wake of a rotationally oscillating cylinder. (2010) Journal of Fluid Mechanics, vol. 643 . pp. 349-362. ISSN 0022-1120

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Official URL: http://dx.doi.org/10.1017/S0022112009992370

Abstract

A study of the flow past an oscillatory rotating cylinder has been conducted, where the frequency of oscillation has been matched to the natural frequency of the vortex street generated in the wake of a stationary cylinder, at Reynolds number 300. The focus is on the wake transition to three-dimensional flow and, in particular, the changes induced in this transition by the addition of the oscillatory rotation. Using Floquet stability analysis, it is found that the fine-scale three-dimensional mode that typically dominates the wake at a Reynolds number beyond that at the second transition to three-dimensional flow (referred to as mode B) is suppressed for amplitudes of rotation beyond a critical amplitude, in agreement with past studies. However, the rotation does not suppress the development of three-dimensionality completely, as other modes are discovered that would lead to three-dimensional flow. In particular, the longer-wavelength mode that leads the three-dimensional transition in the wake of a stationary cylinder (referred to as mode A) is left essentially unaffected at low amplitudes of rotation. At higher amplitudes of oscillation, mode A is also suppressed as the two-dimensional near wake changes in character from a single- to a double- row wake; however, another mode is predicted to render the flow three-dimensional, dubbed mode D (for double row). This mode has the same spatio-temporal symmetries as mode A.

Item Type:Article
Additional Information:Thanks to Cambridge University Press editor. The definitive version is available at http://dx.doi.org/10.1017/S0022112009992370
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
Other partners > Monash University (AUSTRALIA)
Laboratory name:
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Deposited By:David LO JACONO

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