Possible states in the flow around two circular cylinders in tandem with separations in the vicinity of the drag inversion spacing

Carmo, Bruno Souza; Meneghini, Júlio Romano; Sherwin, Spencer J.

doi:10.1063/1.3420111

Cited by 103 publications

(43 citation statements)

References 18 publications

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“…At lower Reynolds numbers, the Reynolds number sensitivity of the flow patterns has been investigated numerically by Carmo et al (2010aCarmo et al ( , 2010b. Their flow pattern boundaries are shown in Fig.…”

Section: Reynolds Number Effectsmentioning

confidence: 99%

“…There have also been many numerical studies of the flow around two circular cylinders in tandem, primarily at low Reynolds numbers (e.g., Mittal et al (1997) for Re = 100 and 1000; Farrant et al (2000) for Re = 200; Meneghini et al (2001) for Re =100 and 200; Sharman et al (2005) for Re= 100; Carmo and Meneghini (2006) for Re = 160-320; Papaioannou et al (2006) for Re = 100-1000; Carmo et al (2010a) for Re = 50-500; Carmo et al (2010b) for Re =200-350; Singha and Sinhamahapatra (2010) for Re 40-150), although some higher Reynolds number simulations also exist (e.g., Kitagawa and Ohta (2008) for Re = 2.2 Â 10 4 ).…”

Section: Tandem Configurationmentioning

confidence: 99%

“…A similar classification scheme was used by Carmo et al (2010aCarmo et al ( , 2010b, based on numerical simulations of two tandem circular cylinders at low Reynolds numbers, with three main flow patterns: (i) SG (symmetric in the gap) observed at L/D = 1.5; (ii) AG (alternating in the gap) observed at L/D = 1.8 and 2.3; and (iii) WG (wake in the gap) observed at L/D =5.…”

Section: Flow Patternsmentioning

confidence: 99%

See 2 more Smart Citations

Two circular cylinders in cross-flow: A review

Sumner

2010

Journal of Fluids and Structures

723

239

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Section: Reynolds Number Effectsmentioning

confidence: 99%

Section: Tandem Configurationmentioning

confidence: 99%

Section: Flow Patternsmentioning

confidence: 99%

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Two circular cylinders in cross-flow: A review

Sumner

2010

Journal of Fluids and Structures

723

239

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“…This canonical flow is of engineering importance due to its relevance in a variety of applications in the fields of aerospace, civil and marine engineering. Most of the earlier studies focus 5 on the flow past a single circular or square cylinder due to their geometrical simplicity and wide applications (e.g., [2][3][4][5][6][7]), while there are also plenty of numerical and experimental studies on variations such as the inclined cylinder [8][9][10], the rotating cylinder [11][12][13], and multiple cylinders in tandem or side-by-side arrangement [14][15][16][17][18]. These studies mainly intended to investigate the effects of the Reynolds number and the ge- 10 ometrical parameters (e.g.…”

Section: Introductionmentioning

confidence: 99%

Low-Re flow past an isolated cylinder with rounded corners

Zhang

Samtaney

2016

Computers & Fluids

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Highlights• DNS on the separation and transition of flow past a partially rounded cylinder.• The effect of the corner radius of the cylinder is studied.• Investigation on time-averaged flow, unsteady flow, turbulent statistics and 3D flow pattern.• There are drastic variations of the flow pattern between the square cylinder and the partially rounded cylinder, and between the latter and the circular cylinder.• Non-time-periodicity is significant in the shear layer and at the reattachment point. AbstractDirect numerical simulation is performed for flow past an isolated cylinder at Re = 1, 000. The corners of the cylinder are rounded at different radii, with the non-dimensional radius of curvature varying from R + = R/D = 0.000 (square cylinder with sharp corners) to 0.500 (circular cylinder), in which R is the corner radius and D is the cylinder diameter. Our objective is to investigate the effect of the rounded corners on the development of the separated and transitional flow past the cylinder in terms of timeaveraged statistics, time-dependent behavior, turbulent statistics and three-dimensional flow patterns. Numerical results reveal that the rounding of the corners significantly reduces the time-averaged drag and the force fluctuations. The wake flow downstream of the square cylinder recovers the slowest and has the largest wake width. However, the statistical quantities do not monotonically vary with the corner radius, but exhibit drastic variations between the cases of square cylinder and partially rounded cylinders, and between the latter and the circular cylinder. The free shear layer separated from the R + = 0.125 cylinder is the most stable in which the first roll up of the wake vortex occurs furthest from the cylinder and results in the largest recirculation bubble, whose size reduces as R + further increases. The coherent and incoherent Reynolds stresses are most pronounced in the near-wake close to the reattachment point, while also being noticable in the shear layer for the square and R + = 0.125 cylinders. The wake vortices translate in the streamwise direction with a convection velocity that is almost constant at approximately 80% of the incoming flow velocity. These vortices exhibit nearly the same trajectory for the rounded cylinders and are furthest away from the wake centerline for the square one. The flow past the square cylinder is strongly three-dimensional as indicated by the significant primary and secondary enstrophy, while it is dominated by the primary enstrophy (ω 2 z ) for the rounded cylinders.

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“…The oscillation of the cylinder aids to increase the correlation length of the flow vortical structures in the spanwise direction. Carmo et al (2010) reported that three dimensionality can exist at Re ≈ 163 for two fixed cylinders in a tandem arrangement. However, it seems reasonable to assume that at low Reynolds numbers, the three dimensional effects remain weak for freely oscillating cylinders in an in-line arrangement.…”

Section: Introductionmentioning

confidence: 99%

Flow-induced vibrations of in-line cylinder arrangements at low Reynolds numbers

Étienne

Scolan

et al. 2016

Journal of Fluids and Structures

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Oviedo-Tolentino et al. ontétudié expérimentalement les oscillations de 10 cylindres placés les uns derrière les autres pour un facteur de masse amortissement de m * ζ = 0.13. Ils ont confirmé que le troisième cylindre, c'està dire celui placé derrière les deux premiers, peut subir des oscillations transverses plus importantes encore que celles subies par le deuxième cylindre. Ces grandes oscillations peuvent non seulement causer une fatigue excessive des matériaux maiségalement provoquer des collisions entre les cylindres. Ainsi, les WIV peuvent poser de sérieux problèmes lors de la conception de nombreux systèmes en ingénierie.A la lumière de cesétudes récentes, il est donc nécessaire d'approfondir l'étude des comportements de plusieurs corps placés les uns derrière les autres dans unécoulement transverse et montésélastiquement. Miseà part les fortes oscillations observées, de nombreux aspects des WIV de plusieurs cylindres en ligne restent très mal connus : les réponses fréquentielles et les amplitudes maximales produites, l'influence du nombre de Reynolds de l'écoulement, les effets dusà des ratios de masse ou des facteurs de masse amortissement faibles, etc.Cette thèse viseà explorer numériquement les réponses d'oscillations induites par sillage de 3 cylindres circulaires disposés en ligne et ayant un nombre de masse faible et un amortissement nul pour de faibles nombres de Reynolds. Pour atteindre cet objectif de recherche, on procède en troisétapes. La premièreétape consisteà s'assurer que l'outil numérique utilisé pour effectuer les simulations est correctement implémenté. Les tests de vérification du code sont basés sur v la méthode de la solution manufacturée pour des problèmes d'interactions fluide-structure où la structure peutêtre modélisée comme un corps rigide. Aucune solution manufacturée pour de type de problèmes n'est disponible. Ainsi on a développé une procédure générique pour produire des solutions manufacturées afin de vérifier les codes de calcul d'interactions fluide-structure. Cette procédure est appliquéeà des cas bi-et tridimensionnels. Une comparaison entre les résultats obtenus et desétudes expérimentales pour un nombre de masse faible et des nombres de Reynolds modérémentélevés indique que les réponses ne sont pas identiques. Cependant, nos résultatsà bas nombres de Reynolds reproduisent l'essentiel des caractéristiques des réponses pour des nombres de Reynolds plusélevés. Par conséquent, la simulationà bas nombres de Reynolds des VIV, et par extension des WIV, permet de représenter qualitativement les caractéristiques principales des réponsesà nombres de Reynolds plusélevés.Dans une troisième partie, onétudie les réponses des vibrations induites par sillage de 3 cylindres circulaires disposés en ligne. On considère des ratios de masse faibles et un amortissement nulà bas nombres de Reynolds. On compare ces résultats avec ceux de 2 cylindres en tandem et ceux d'un seul cylindre dans les mêmes conditions. La présence du troisième cylindre induit des différences significatives par rap...

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Possible states in the flow around two circular cylinders in tandem with separations in the vicinity of the drag inversion spacing

Cited by 103 publications

References 18 publications

Two circular cylinders in cross-flow: A review

Two circular cylinders in cross-flow: A review

Low-Re flow past an isolated cylinder with rounded corners

Flow-induced vibrations of in-line cylinder arrangements at low Reynolds numbers

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