The three-dimensional transition in the flow around a rotating cylinder

Akoury, R. El; Braza, Marianna; Perrin, R.; Harran, Gilles; Hoarau, Yannick

doi:10.1017/s0022112008001390

Cited by 60 publications

(49 citation statements)

References 22 publications

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“…At low rotation rates, α < 1, Akoury et al (2008) found that Mode A becomes unstable at higher Reynolds numbers as α is increased. At higher rotation rates, the flow becomes increasingly unstable to perturbations at Re = 200 in the range 3 α 5 (Meena et al 2011).…”

Section: Introductionmentioning

confidence: 93%

Two- and three-dimensional wake transitions of an impulsively started uniformly rolling circular cylinder

et al. 2017

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This paper presents the characteristics of the different stages in the evolution of the wake of a circular cylinder rolling without slipping along a wall at constant speed, acquired through numerical stability analysis and two-and three-dimensional numerical simulations. Reynolds numbers between 30 and 300 are considered. Of importance in this study is the transition to three-dimensionality from the underlying two-dimensional periodic flow and, in particular, the way that the associated transitions influence the fluid forces exerted on the cylinder, and the development and the structure of the wake. It is found that the steady two-dimensional flow becomes unstable to threedimensional perturbations at Re c,3D = 37, and that the transition to unsteady twodimensional flow -or periodic vortex shedding -occurs at Re c,2D = 88, thus validating and refining the results of Stewart et al. (2010). The main focus here is for Reynolds numbers beyond the transition to unsteady flow at Re c,2D = 88. From impulsive start up, the wake almost immediately undergoes transition to a periodic two-dimensional wake state, which, in turn, is three-dimensionally unstable. Thus, the previous threedimensional stability analysis based on the two-dimensional steady flow provides only an element of the full story. Floquet analysis based on the periodic two-dimensional flow was undertaken and new three-dimensional instability modes were revealed. The results suggest that an impulsively started cylinder rolling along a surface at constant velocity for Re 90 will result in the rapid development of a periodic two-dimensional wake that will be maintained for a considerable time prior to the wake undergoing threedimensional transition. Of interest, the mean lift and drag coefficients obtained from full three-dimensional simulations match predictions from two-dimensional simulations to within a few percent.

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Section: Introductionmentioning

confidence: 93%

Two- and three-dimensional wake transitions of an impulsively started uniformly rolling circular cylinder

et al. 2017

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“…One question of interest is whether this mode-switching signature of the upper branch still prevails when the cylinder is undergoing forced vibration. Indeed, the action of rotating fixed cylinders modifies the wake stability, whether the rotation is oscillatory (Tokumaru & Dimotakis 1991;Lo Jacono et al 2010;D'Adamo, Godoy-Diana & Wesfreid 2015) or uniform (El Akoury et al 2008;Rao et al 2013Rao et al , 2015. Thus, given that the cylinder is under uniform rotation, hence biasing the vorticity production towards one side and therefore biasing the wake topology, the question of how this affects the wake dynamics of the upper branch is of interest.…”

Section: Wake Structuresmentioning

confidence: 99%

“…Over a small range of α 4 there is a secondary region of wake unsteadiness, comprising low-frequency one-sided vortices, as shown by Mittal & Kumar (2003), Stojković et al (2003) and Pralits, Brandt & Giannetti (2010). Numerical simulations have shown that the critical Reynolds number of the secondary instability associated with the spanwise undulation of the von Kármán vortices increases with Reynolds number (El Akoury et al 2008;Rao et al 2015). Depending on α and Re, there exist a number of steady and unsteady wake modes (Pralits, Giannetti & Brandt 2013;Rao et al 2013Rao et al , 2015.…”

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confidence: 99%

Experimental investigation of flow-induced vibration of a rotating circular cylinder

et al. 2017

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 18605 While flow-induced vibration of bluff bodies has been extensively studied over the last half-century, only limited attention has been given to flow-induced vibration of elastically mounted rotating cylinders. Since recent low-Reynolds-number numerical work suggests that rotation can enhance or suppress the natural oscillatory response, the former could find applications in energy harvesting and the latter in vibration control. The present experimental investigation characterises the dynamic response and wake structure of a rotating circular cylinder undergoing vortex-induced vibration at a low mass ratio (m * = 5.78) over the reduced velocity range leading to strong oscillations. The experiments were conducted in a free-surface water channel with the cylinder vertically mounted and attached to a motor that provided constant rotation. Springs and an air-bearing system allow the cylinder to undertake low-damped transverse oscillations. Under cylinder rotation, the normalised frequency response was found to be comparable to that of a freely vibrating non-rotating cylinder. At reduced velocities consistent with the upper branch of a non-rotating transversely oscillating cylinder, the maximum oscillation amplitude increased with non-dimensional rotation rate up to α ≈ 2. Beyond this, there was a sharp decrease in amplitude. Notably, this critical value corresponds approximately to the rotation rate at which vortex shedding ceases for a non-oscillating rotating cylinder. Remarkably, at α = 2 there was approximately an 80 % increase in the peak amplitude response compared to that of a non-rotating cylinder. The observed amplitude response measured over the Reynolds-number range of (1100 Re 6300) is significantly different from numerical predictions and other experimental results recorded at significantly lower Reynolds numbers.

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“…However, this problem has important applications in designing several heat transfer devices used in modern industry. Al though few studies on forced and mixed convective heat transfer of nanofluids past circular ( [15][16][17][18]) and square ( [19][20]) cylinders have recently been reported, a systematic study addressing this extremely significant issue is yet to be found in the literature.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer Characteristics of Nanofluid Flow Around a Rotating Cylinder

Khelili¹,

Abderazzak²

2018

Studia UBB Chemia

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ABSTRACT. The forced convective flow and heat transfer of nanofluids past a rotating cylinder placed in a uniform cross stream is investigated numerically. The computations are carried out at a representative Reynolds number (Re) of 200. The dimensionless cylinder rotation rate (α) is varied between 0 and 6. The range of nanoparticle volume fractions (φ) considered is 0 ≤ φ ≤ 5%. Two-dimensional and unsteady mass continuity, momentum, and energy equations have been discretized using finite volume method. SIMPLE algorithm has been applied for solving the pressure linked equations. The effect of rotation rates (α) on fluid flow and heat transfer were investigated numerically. In addition, time-averaged (lift and drag coefficients and Nusselt number) results were obtained and compared with the literature data. A good agreement was obtained for both the local and averaged values. INTRODUCTIONThe classical problem of viscous incompressible flow over a circular cylinder confined in a channel is one of the most widely studied problems in computational fluid dynamics (CFD). This type of flow problems frequently arise in various engineering fields. Because of its popularity, a plethora of numerical, theoretical and experimental results are available for this problem in the literature. . An explicit pseudo-spectral technique was adopted for resolving the fundamental equations. According to their results, when α = 3.25 more than one vortex is shed downstream. Kang [3] also has contributed significant work to this research area. Sequential numerical simulations at Re equal to 40, 60, 100 and 160 in the range of 0 ≤ α ≤ 2.5 were performed. It was observed that at 60 ≤ Re ≤ 160 the maximum value of a, which favors flow instability, varies logarithmically when plotted against Re. Zdravkovich [4], has compiled almost all the experimental, analytical and numerical simulation data on flow past cylinders,In the study of wake dynamics, bluff body rotation has always drawn considerable attention largely due to its effects on boundary layer separation and the Magnus effect. Increase in the lift magnitude more than classic Prandtl's limit due to increase in rotation rate of the circular cylinder was proposed by Glauart [5]. For the similar flow configuration, Kang and Choi [6], followed with the numerical solution of the unsteady governing equations in the primitive variables velocity and pressure for flows with Re = 60, 100 and 160 with 0 = α = 2.5. Their results showed that vortex shedding vanishes when α increases beyond a critical value which follows a logarithmic dependence on the Reynolds number (e.g., the critical dimensionless rotation rate α = 1.9 for Re = 160). Later, the work of (Mittal & Kumar, [7]) performed a comprehensive numerical investigation by fixing a moderate value of Re = 200 while considering a wide interval for the dimensionless rotation rate of 0 ≤ α ≤ 5. They used the finiteelement method to solve the unsteady incompressible Navier-Stokes equations in two-dimensions for the primitive variables velocity and ...

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The three-dimensional transition in the flow around a rotating cylinder

Cited by 60 publications

References 22 publications

Two- and three-dimensional wake transitions of an impulsively started uniformly rolling circular cylinder

Two- and three-dimensional wake transitions of an impulsively started uniformly rolling circular cylinder

Experimental investigation of flow-induced vibration of a rotating circular cylinder

Heat Transfer Characteristics of Nanofluid Flow Around a Rotating Cylinder

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