Stability of a circular cylinder oscillating in uniform flow or in a wake

Tanida, Yoshimichi; Okajima, Atsushi; Watanabe, Yuichiro

doi:10.1017/s0022112073000935

Cited by 266 publications

(147 citation statements)

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“…The situation where the cylinders are aligned to the flow direction ͑the so-called tandem arrangement͒ has been of particular interest and a critical spacing ͑around 3.8 cylinder diameters͒ has long been detected by Ishigai et al 3 This feature has since been confirmed in high Reynolds number flows. [4][5][6] To our knowledge, the only low Reynolds number experiments of Tanida et al 7 shows a discontinuity in the drag coefficient curve for a spacing around of 3.9 diameters. These results were further confirmed by Ohmi and Imaichi 8 and by the recent numerical simulations of Meneghini et al 9 and Sharman et al 10 To our knowledge, the most complete description of the tandem cylinder wake at low Reynolds numbers was recently given by Mizushima and Suehiro.…”

Section: Introductionmentioning

confidence: 69%

Hysteretic mode exchange in the wake of two circular cylinders in tandem

et al. 2006

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Our experimental study is devoted to the analysis of the flow past two tandem circular cylinders near the vortex shedding threshold. A recent bidimensional numerical analysis of this flow ͓Mizushima and Suehiro, Phys. Fluids 17, 104107 ͑2005͔͒ has predicted that the bifurcation diagram should become complex in the vicinity of the instability threshold. Subcritical and saddle node bifurcations that lead to hysteretic exchanges between two different modes of vortex shedding were detected for particular distances of separation of the cylinders. We present here visualizations and velocity measurements of this flow in a water channel that prove the robustness of the complexity of the bifurcation diagram in real flows.

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Section: Introductionmentioning

confidence: 69%

Hysteretic mode exchange in the wake of two circular cylinders in tandem

et al. 2006

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“…So does C D (Tanida, Okajima & Watanabe 1973). Zdravkovich (1982) concluded that the main feature of vortex shedding synchronizing with an oscillating cylinder was to magnify greatly C D and C L , compared with a stationary cylinder.…”

Section: Discussionmentioning

confidence: 99%

Turbulent wake of an inclined cylinder with water running

Alam

Zhou

2007

J. Fluid Mech.

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This paper presents the results of an experimental study of fluid dynamics around an inclined circular cylinder with and without water running over its surface, covering water rivulet formation, fluid forces on the cylinder, near wake and their interrelationships. The cylinder inclination angle (α) with respect to incident flow was between 55 • and 80 • . It has been found that water running over the cylinder surface may behave quite differently, depending on the Reynolds number (Re), and subsequently impact greatly upon the fluid dynamics around the cylinder. As such, five flow categories are classified. Category A: one water rivulet was observed, irrespective of α, at the leading stagnation point at a small Re. Category B: the rivulet splits into two, symmetrically arranged about the leading stagnation line, once Re exceeds a critical value that depends on α. The two rivulets may further switch back to one, and vice versa. Category C: two symmetrical straight rivulets occur. Category D: the two rivulets shift towards the flow separation line with increasing Re and oscillate circumferentially. The oscillation reaches significant amplitude when the rivulets occur at about 70 • from the leading stagnation point. This increased amplitude is coupled with a rapid climb in the mean and fluctuating drag and lift, by a factor of near 5 for the fluctuating lift at α = 80 • . Meanwhile, the flow structure exhibits a marked variation. For example, Strouhal number and vortex formation length decrease, along with an increase in spanwise vorticity concentration, velocity deficit, and coherence between vortex shedding and fluctuating lift. All these observations point to the occurrence of a 'lock-in' phenomenon, i.e. the rivulet oscillation synchronizing with flow separation. A rivulet-vortex-induced instability is proposed to be responsible for the well reported rain-wind-induced vibration associated with the stay cables of cablestayed bridges. Category E: the two rivulets shift further downstream just beyond the separation line; the shear layers behind the rivulets become highly turbulent, resulting in weakened vortex shedding, flow fluctuating velocities and fluctuating fluid forces. Based on the equilibrium of water rivulet weight, aerodynamic pressure and friction force between fluid and surface, an analysis is developed to predict the rivulet position on the cylinder, which agrees well with measurements.

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“…7,10,11,13 Basically, the flow patterns can be divided into two regimes by a "critical spacing" ͑S c ͒. In the case of Re= 100, the value of S c is between 3.75 and 4, according to Sharman et al 13 The different types of vortex streets are shown in the vorticity contours for Re= 100 in Fig.…”

Section: Flow Patterns For Flow Over Two Stationary Tandem Cylinmentioning

confidence: 96%

“…The literature concerning flow over two stationary tandem cylinders includes experimental observations 7,10,11 and numerical simulations. [12][13][14][15] Physical mechanisms involved in two tandem cylinders are very different from those in a single cylinder because the wakes that are shed from both cylinders are coupled and interact with each other.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear spacing and frequency effects of an oscillating cylinder in the wake of a stationary cylinder

Yang

Zheng

2010

Physics of Fluids

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A numerical study of the laminar necklace vortex system and its effect on the wake for a circular cylinder Phys. Fluids 24, 073602 (2012) Nonlinear responses to a transversely oscillating cylinder in the wake of a stationary upstream cylinder are studied theoretically by using an immersed-boundary method at Re= 100. Response states are investigated in the three flow regimes for a tandem-cylinder system: the "vortex suppression" regime, the critical spacing regime, and the "vortex formation" regime. When the downstream cylinder is forced to oscillate at a fixed frequency and amplitude, the response state of flow around the two cylinders varies with different spacing between the two cylinders, while in the same flow regime, the response state can change with the oscillating frequency and amplitude of the downstream cylinder. Based on velocity phase portraits, each of the nonlinear response states can be categorized into one of the three states in the order of increasing chaotic levels: lock-in, transitional, or quasiperiodic. These states can also be correlated with velocity spectral behaviors. The discussions are conducted using near-wake velocity phase portraits, spectral analyses, and related vorticity fields. A general trend in the bifurcation diagrams of frequency spacing shows the smaller the spacing, frequency, or amplitude, the less chaotic the response state of the system and more likely the downstream and upstream wakes are in the same response state. The system is not locked-in in any case when the spacing between the cylinders is larger than the critical spacing. The near-wake velocity spectral behaviors correspond to the nonlinear response states, with narrow-banded peaks shown at the oscillation frequency and its harmonics in the lock-in cases. High frequency harmonic peaks, caused by interactions between the upstream wake and the downstream oscillating cylinder, are reduced in the near-wake velocity spectra of the upstream cylinder when the spacing increases.

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Stability of a circular cylinder oscillating in uniform flow or in a wake

Cited by 266 publications

References 4 publications

Hysteretic mode exchange in the wake of two circular cylinders in tandem

Hysteretic mode exchange in the wake of two circular cylinders in tandem

Turbulent wake of an inclined cylinder with water running

Nonlinear spacing and frequency effects of an oscillating cylinder in the wake of a stationary cylinder

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