Characteristics of the Flow around Two Circular Cylinders Arranged in Tandem : 2nd Report, Unique Phenomenon at Small Spacing

Igarashi, Tamotsu

doi:10.1299/jsme1958.27.2380

Cited by 125 publications

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“…These measurements are acquired for different arrangements of the cylinders, as the pitch ratio(s), incidence angle and -Aode et al (1985) 100, 300, 1 Â 10 3 1.5-10 30 2 Not given Towing tank FV, CTA St Igarashi (1981) 8.7 Â 10 3 -5.2 Â 10 4 1-5 4 6 0.6 Wind tunnel FV, CTA, pressure St, C P , C P 0 , C D Igarashi (1984) 1.15 Â 10 4 -1.03 Â 10 5 1-1.5 3 13 0.6 Wind tunnel FV, CTA, pressure St, C P , C P 0 , C D Ishigai et al (1972Ishigai et al ( , 1973 1.5 Â 10 3 -1.5 Â 10 4 1-5 11 9 Not given Wind tunnel FV, CTA, pressure St, C P Jendrzejcyk and Chen (1986) 1.5 Â 10 4 -1.5 Â 10 5 1.4-10 12 9 1-11 Water tunnel Force St, C D 0 , C L 0 Kiya et al (1992) 2 Â 10 4 -3.7 Â 10 4 2.5-4 11 10 0.1-10 Wind tunnel CTA, pressure - Kostic and Oka (1972) 1.3 Â 10 4 -4 Â 10 4 1.6-9 5 20 2.8 Wind tunnel Pressure, temperature C P , C D , Nu Kwon et al (1996) 1.7 Â 10 4 1-5 11 2 2.5 Water channel PIV Velocity field Lee and Basu (1997) 2.4 Â 10 4 -5. Nishimura et al (1986) 800-1 Â 10 4 1.2-7.2 5 9 0.6 Water tunnel FV Sh Okajima (1979) 4 Â 10 4 -6.2 Â 10 5 1.…”

Section: Approaches To Understanding the Fluid Behaviourmentioning

confidence: 99%

“…Ishigai et al (1972Ishigai et al ( , 1973 1.5 Â 10 3 -1.5 Â 10 4 L/D =0.68-4, T/D =0.5-3 11 9 Not given Wind tunnel FV, CTA, pressure St, C P Kiya et al (1980) 2 Â 10 4 -3.7 Â 10 4 P/D =0-5.5, a = 0-901 11 19 0.8 Wind tunnel CTA St Moriya and Sakamoto (1985) 6.53 Â 10 4 L/D =2-6, T/D =0-1.5 10 20 0.4 Wind tunnel FV, pressure, force Ozono et al (2001) 2.5 Â 10 3 -7.5 Â 10 3 , 3 Â 10 4 Reynolds number are varied, and the changes to the flow field and other features are then inferred from the behaviour of the experimental data. As examples: (i) vortex shedding frequency data have been used to infer the existence of two K arm an vortex shedding processes for staggered-cylinder configurations, by Kiya et al (1980); (ii) static pressure coefficient data have been offered as evidence of a stable pair of eddies within the gap between two tandem cylinders, and continuous reattachment of the two shear layers, by Igarashi (1981Igarashi ( , 1984, Hiwada et al (1982) and Ljungkrona (1992); and (iii) peak mean lift force measurements for two staggered circular cylinders, and rapid changes in the mean lift force for small adjustments to the geometry, have been attributed to the strong influence of the high speed flow deflected through the gap between cylinders, as described by Zdravkovich and Pridden (1977). Such an approach is useful from an engineering design point of view, and has led to recommendations for avoiding the occurrence of flowinduced vibration, for instance.…”

Section: Approaches To Understanding the Fluid Behaviourmentioning

confidence: 99%

“…A third approach to understanding the fluid dynamics of multiple cylinders in cross-flow, and arguably the most useful, is to identify from flow visualization (and other means) the various flow patterns which arise for different choices of the geometry. The understanding of the fluid dynamics of tandem cylinders in cross-flow has greatly benefited from this approach, as demonstrated, for example, by Igarashi (1981Igarashi ( , 1984. His studies identified up to eight different flow patterns from a combination of flow visualization and measured data for various combinations of L/D and Re.…”

Section: Approaches To Understanding the Fluid Behaviourmentioning

confidence: 99%

See 2 more Smart Citations

Two circular cylinders in cross-flow: A review

Sumner

2010

Journal of Fluids and Structures

654

217

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Section: Approaches To Understanding the Fluid Behaviourmentioning

confidence: 99%

Section: Approaches To Understanding the Fluid Behaviourmentioning

confidence: 99%

Section: Approaches To Understanding the Fluid Behaviourmentioning

confidence: 99%

See 1 more Smart Citation

Two circular cylinders in cross-flow: A review

Sumner

2010

Journal of Fluids and Structures

654

217

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“…Williamson 1985; Kolář, Lyn & Rodi 1997;Sumner et al 1999;Zhou et al 2001Zhou et al , 2002Zhou & Yiu 2006), Strouhal number St (e.g. Igarashi 1981Igarashi , 1984Kim & Durbin 1988;Xu & Zhou 2004) and forces on the cylinders (e.g. Zdravkovich 1977Zdravkovich , 1985Zdravkovich , 1987Mahir & Rockwell 1996).…”

mentioning

confidence: 99%

Flow structure behind two staggered circular cylinders. Part 1. Downstream evolution and classification

Zhou

2008

J. Fluid Mech.

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Flow structures, Strouhal numbers and their downstream evolutions in the wake of two-staggered circular cylinders are investigated at Re = 7000 using hot-wire, flowvisualization and particle-image velocimetry techniques. The cylinder centre-to-centre pitch, P , ranges from 1.2d to 4.0d (d is the cylinder diameter) and the angle (α) between the incident flow and the line through the cylinder centres is 0 • ∼ 90 • . Four distinct flow structures are identified at x/d > 10 (x is the downstream distance from the mid-point between the cylinders), i.e. two single-street modes (S-I and S-II) and two twin-street modes (T-I and T-II), based on Strouhal numbers, flow topology and their downstream evolution. Mode S-I is further divided into two different types, i.e. SIa and S-Ib, in view of their distinct vortex strengths. Mode S-Ia occurs at P /d 6 1.2. The pair of cylinders behaves like one single body, and shear layers separated from the free-stream sides of the cylinders roll up, forming one street of alternately arranged vortices. The street is comparable to that behind an isolated cylinder in terms of the topology and strength of vortices. Mode S-Ib occurs at α 6 10 • and P /d > 1.5. Shear layers separated from the upstream cylinder reattach on or roll up to form vortices before reaching the downstream cylinder, resulting in postponed flow separation from the downstream cylinder. A single vortex street thus formed is characterized by significantly weakened vortices, compared with Mode S-Ia. Mode S-II is identified at P /d = 1.2 ∼ 2.5 and α > 20 • or 1.5 6 P /d 6 4.0 and 10 • < α 6 20 • , where both cylinders generate vortices, with vortex shedding from the upstream cylinder at a much higher frequency than from the downstream, producing two streets of different widths and vortex strengths at x/d 6 5.0. The two streets interact vigorously, resulting in a single street of the lower-frequency vortices at x/d > 10. The vortices generated by the downstream cylinder are significantly stronger than those, originating from the upstream cylinder, in the other row. Mode T-I occurs at P /d > 2.5 and α = 20 • ∼ 88 • ; the two cylinders produce two streets of different vortex strengths and frequencies, both persisting beyond x/d = 10. At P /d > 2.5 and α > 88 • , the two cylinders generate two coupled streets, mostly anti-phased, of the same vortex strength and frequency (St ≈ 0.21), which is referred to as Mode T-II. The connection of the four modes with their distinct initial conditions, i.e. interactions between shear layers around the two cylinders, is discussed. † Author to whom correspondence should be addressed: mmyzhou@polyu.edu.hk 52 J. C. Hu and Y. Zhou IntroductionBecause of its fundamental importance and engineering significance, flow behind two circular cylinders has been investigated extensively. Most previous investigations focused on the wake of two side-by-side or inline cylinders because of their relative simplicity. As a result, our knowledge has been greatly improved on the two types of flow in terms of the dep...

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“…At intermediate separation distances, the flow regime is "critical", whereby, it can switch between bi-stable flow states representing short and large separation distances. Measurements of various flow quantities, highlighting different aspects of the tandem cylinder flow field, are reported in references [4][5][6][7][8][9][10][11][12][13][14][15]. Numerical simulations at fairly low Reynolds numbers are considered in references 16-18. Despite their usefulness, the earlier studies lack detailed on-surface and off-surface measurements that are needed for fully characterizing the turbulent fluctuating field and benchmarking the computations.…”

Section: Introductionmentioning

confidence: 99%