Force coefficients and Strouhal numbers of four cylinders in cross flow

Lam, Kin Man; Li, J.Y; So, R. M. C.

doi:10.1016/j.jfluidstructs.2003.07.008

Cited by 109 publications

(64 citation statements)

References 43 publications

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“…Farrant et al [8] captured twodimensional (2-D) flow characteristics and interactive forces associated with flow around four equispaced cylinders for two orientations (in-line arrangement and an alignment angle of 45° arrangement ) for spacing ratios L/D=3 and 5 at Re=200 using a cell boundary element method. With the typical case of four cylinders being arranged with alignment angle of 45° and the case of inline arrangement at L/D=5, the computation results showed agreement with visualization results obtained by Lam and Lo [1]and Lam et al [2,6]. However, it is interesting to note that for the in-line arrangement with L/D=3, the computational results showed that shear layers from upstream cylinders roll up into mature vortices and impinge on the downstream cylinders' surface.…”

Section: Introductionsupporting

confidence: 83%

“…Sayers [3,4] conducted experiments on four cylinders in a square configuration in the spacing ratio range of 1.55 with an aspect ratio of 11.5 at Reynolds number of 30000. The pressure distributions and the lift/drag coefficients on four cylinders with the spacing ratio varying from 1.26 to 5.8 are measured by Lam and Fang [5] and Lam et al [6]. Lam and Zou [7] further investigated effects of the spacing ratio and Reynolds number on mean velocity distribution and flow patterns around the four in-line cylinders at subcritical Reynolds numbers using laser Doppler anemometer (LDA) and digital particle image velocimetry (DPIV) techniques.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of turbulent flow past four grooved and smooth cylinders in an in-line square arrangement

Ladjedel¹,

Bouacha²,

Adjlout³

et al. 2015

EPJ Web of Conferences

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Abstract. An experimental study of turbulent flow past four cylinders in square arrangement with a space ratio of (T/D = P/D = 2.88) is performed. The investigation focuses on effects of Reynolds number and the shape of cylinders on the force and pressure coefficients of the cylinders. Two cases are investigated: four smooth cylinders (case1) and four grooved cylinders (case2). The cylinders are equipped with two grooves placed on the external surface at 90° and 270° degrees. The pressure distributions along the tubes (22 circumferential pressure taping) were determined for a variation of the azimuthal angle from 0 to 360deg.The drag and lift forces are measured using the TE 44 balance. The results show a bistable flow often exists behind the downstream cylinders is observed. By rising the Reynolds number the pressure coefficient increases in the absolute value.

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Section: Introductionsupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Experimental investigation of turbulent flow past four grooved and smooth cylinders in an in-line square arrangement

Ladjedel¹,

Bouacha²,

Adjlout³

et al. 2015

EPJ Web of Conferences

View full text Add to dashboard Cite

show abstract

“…The hot-wire, laser-induced fluorescence flow visualization and Particle Image Velocimetry (PIV) techniques are usually used to examine the flow filed, while fiber grating and piezo-electric technologies are employed to measure the dynamic features. And the sharp and configurations of cylinders also are settled in a more complicated way [6,7]. Alam and Zhou identified four flow regimes of flow behind two side-by-side square cylinders using flow visualization method and the rules of street-merging were discussed [8].…”

Section: Introductionmentioning

confidence: 99%

Flow Features of Three Side-by-side Circular Cylinders at Low Reynolds Number

et al. 2016

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Abstract. In order to study the fluctuation of kinetic parameter of cylinder matrix in incompressible stationary flow, the flow fluid around three side-by-side circular cylinders are simulated using Immersed BoundaryLattice Boltzmann method (IB-LBM). Drag and lift force of the three cylinders are investigated as the interval between each cylinder varied from zero to five times of the cylinder diameter. Five flow patterns are defined according to the vortices structure in the downstream of the cylinders. Power spectrum analysis of lift force is developed to explain the vortex patterns. Through the research, we find the strength and phase of the gap flow play an important role in the vortex formatting process. The vortices shedding from different cylinders neutralize and combine in the near wake, contributing a lot to the variation of forces.

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“…In other cases, for some staggered configurations of circular cylinders, no distinguished Strouhal number has been reported due to weak vortex shedding [30]. Moreover, in some cases for one cylinder, two Strouhal numbers have been reported [32], and sometimes due to the absence of vortex shedding, the Strouhal number of St = 0 has been achieved [21]. On the other hand, the behavior and appearance of the spectral analysis diagrams addressed briefly by Kiya et al [18] would be of great importance.…”

mentioning

confidence: 98%

“…(2) Is the St obtained by counting vortices in flow visualization study [20] or by vortex shedding frequencies behind each cylinder measured using a hot-wire anemometer [32], equivalent to the St determined from fluctuating forces frequencies acting on the cylinders measured by a piezo-electric load cell [21]? Study of the fluid-structure interaction for multi-cylinder arrays in a cross-flow is expected to answer these questions.…”

mentioning

confidence: 99%

Force coefficients and Strouhal numbers of three circular cylinders subjected to a cross-flow

2011

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In this paper, wind tunnel experiments were conducted to measure the mean force coefficients and Strouhal numbers for three circular cylinders of equal diameters in an equilateral-triangular arrangement when subjected to a cross-flow. These experiments were carried out at five subcritical Reynolds numbers ranging from 1.26 × 10 4 to 6.08 × 10 4 . The pressure distributions on the surface of the cylinders were measured using pressure transducers. Furthermore, the hot-wire anemometer was employed to measure the vortex shedding frequencies behind each cylinder. Six spacing ratios (l/d) varying from 1.5 to 4 were investigated. It is observed that for l/d > 2, the upstream cylinder experiences a lower mean drag coefficient compared with the downstream cylinders. The minimum values of the drag coefficient for the downstream cylinders occur at l/d = 1.5 and l/d = 2, because there is no vortex shedding from the foregoing cylinders. Also, the value of the pressure coefficient behind the upstream cylinder reduces by increasing l/d. Moreover, by decreasing the value of l/d, the Strouhal number for the upstream cylinder increases. It can be concluded that the flow pattern and aerodynamic coefficients are basically dependent on l/d; in other words, decreasing l/d results in an increase in the effects of the flow interference between the cylinders.

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Force coefficients and Strouhal numbers of four cylinders in cross flow

Cited by 109 publications

References 43 publications

Experimental investigation of turbulent flow past four grooved and smooth cylinders in an in-line square arrangement

Experimental investigation of turbulent flow past four grooved and smooth cylinders in an in-line square arrangement

Flow Features of Three Side-by-side Circular Cylinders at Low Reynolds Number

Force coefficients and Strouhal numbers of three circular cylinders subjected to a cross-flow

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