On the symmetry breaking instability leading to vortex shedding

Document Type

Article

Publication Date

1-1-1997

Abstract

It is well known that at early stages an impulsively started flow past a circular cylinder consists of twin vortices which are images of one another by reflection through the mid-plane. While the twin vortices are stable for Reynolds numbers below the critical Reynolds number value (Rec≃48), they become unstable above the critical Reynolds number. At Re>Rec. the flow keeps its symmetric recirculating bubble structure for a short time, undergoes a symmetry-breaking instability, and develops into a Karman vortex street. Föppl's vortex model is studied here as a low-dimensional model for the symmetric bubble. The stability analysis of a fixed bubble in the model shows that there are two asymmetric eigenmodes, a stable mode and an unstable one. In this paper, we show by two-dimensional direct numerical simulations (DNS) of the impulsively started flow past a circular cylinder how the instability properties of the model qualitatively mimic those of the real flow. © 1997 American Institute of Physics.

Identifier

0030699286 (Scopus)

Publication Title

Physics of Fluids

External Full Text Location

https://doi.org/10.1063/1.869372

ISSN

10706631

First Page

2550

Last Page

2561

Issue

9

Volume

9

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