Investigation of dominant frequencies in transition Reynolds number range of flow around a circular cylinder PartⅠ: Experimental study of the relation between vortex shedding and transition frequencies

2006 ◽  
Vol 19 (02) ◽  
pp. 159 ◽  
Author(s):  
N A AHMED
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Circular Cylinder ◽  
Vortex Shedding ◽  
Number Range ◽  
Reynolds Number Range ◽  
Dominant Frequencies

Vortex shedding from a circular cylinder in moderate-Reynolds-number shear flow

1980 ◽  
Vol 101 (4) ◽  
pp. 721-735 ◽  
Author(s):  
Masaru Kiya ◽  
Hisataka Tamura ◽  
Mikio Arie
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Shear Flow ◽  
Vortex Shedding ◽  
Transverse Velocity ◽  
Number Range ◽  
Uniform Shear ◽  
Reynolds Number Range ◽  
Moderate Reynolds Number ◽  
Shear Parameter

The frequency of vortex shedding from a circular cylinder in a uniform shear flow and the flow patterns around it were experimentally investigated. The Reynolds number Re, which was defined in terms of the cylinder diameter and the approaching velocity at its centre, ranged from 35 to 1500. The shear parameter, which is the transverse velocity gradient of the shear flow non-dimensionalized by the above two quantities, was varied from 0 to 0·25. The critical Reynolds number beyond which vortex shedding from the cylinder occurred was found to be higher than that for a uniform stream and increased approximately linearly with increasing shear parameter when it was larger than about 0·06. In the Reynolds-number range 43 < Re < 220, the vortex shedding disappeared for sufficiently large shear parameters. Moreover, in the Reynolds-number range 100 < Re < 1000, the Strouhal number increased as the shear parameter increased beyond about 0·1.

On vortex shedding from a circular cylinder in the critical Reynolds number régime

1969 ◽  
Vol 37 (3) ◽  
pp. 577-585 ◽  
Author(s):  
P. W. Bearman
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Strouhal Number ◽  
Vortex Shedding ◽  
Critical Reynolds Number ◽  
Narrow Band ◽  
Critical Regime ◽  
Number Range ◽  
Velocity Fluctuations ◽  
Reynolds Number Range

The flow around a circular cylinder has been examined over the Reynolds number range 105 to 7·5 × 105, Reynolds number being based on cylinder diameter. Narrow-band vortex shedding has been observed up to a Reynolds number of 5·5 × 105, i.e. well into the critical régime. At this Reynolds number the Strouhal number reached the unusually high value of 0·46. Spectra of the velocity fluctuations measured in the wake are presented for several values of Reynolds number.

Hydrodynamic Force Measurements on a Circular Cylinder Fitted With Peripheral Control Cylinders: Preliminary Results on the Development of VIV Suppressors

2015 ◽  
Author(s):  
Mariana Silva-Ortega ◽  
Gustavo R. S. Assi ◽  
Murilo M. Cicolin
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Circular Cylinder ◽  
Drag Reduction ◽  
Vortex Shedding ◽  
Hydrodynamic Force ◽  
Force Measurements ◽  
Number Range ◽  
Preliminary Results ◽  
Reynolds Number Range

Recent achievements in controlling the boundary layer by moving surfaces have been encouraging the development and investigation of passive suppressors of vortex-induced vibration. Within this context, the main purpose of the present work is to evaluate the suppression of vortex shedding of a plain cylinder surrounded by two, four and eight smaller control cylinders. Experiments have been carried out on a fixed circular cylinder to investigate the effect of the control cylinders over drag reduction. Control cylinders with diameter of d/D = 0.06 were tested, where D is the diameter of the main cylinder. The gap between the main cylinder and the control cylinders varied between G/D = 0.05 and 0.15. Experiments with a plain cylinder in the Reynolds number range from 5,000 to 50,000 have been performed to serve as reference. It was found that a cylinder fitted with four control cylinders presented less drag and fluctuating lift than cylinders fitted with two or eight small cylinders.

Study on In-Flow Vibration of Cylinder Arrays Caused by Cross Flow

2011 ◽  
Author(s):  
Tomomichi Nakamura ◽  
Keisuke Nishimura ◽  
Yoshiaki Fujita ◽  
Chihiro Kohara
Keyword(s):  
Reynolds Number ◽  
Vortex Shedding ◽  
Cross Flow ◽  
Thin Plates ◽  
Streamwise Direction ◽  
Number Range ◽  
Direction Transverse ◽  
Drag Forces ◽  
Cylinder Arrays ◽  
Reynolds Number Range

The authors have studied the in-flow vibration phenomena of cylinder arrays caused by cross-flow in the low Reynolds number range around Re=800. This Reynolds number range has been studied because it is the range where symmetric vortex shedding occurs. This report is our first trial to study the in-line fluidelastic vibration of cylinder arrays. In initial tests, the flow velocity was increased up to the maximum achievable level by the test equipment. However, it was found that the array’s cantilever tube supports resulted in large static tube deflections due to static drag forces. The cylinder array tube supports have therefore been replaced by thin plates supported at both ends. The cylinders are set to be flexible both in the streamwise direction and the direction transverse to the flow. The obtained results of these two patterns are also compared with previous cantilevered data. The origin of the observed vibrations whether a self-induced mechanism or vortex shedding is discussed in detail.

Planar Oscillatory Flow Forces at High Reynolds Numbers

1993 ◽  
Vol 115 (1) ◽  
pp. 31-39 ◽  
Author(s):  
J. R. Chaplin
Keyword(s):  
Surface Roughness ◽  
Reynolds Number ◽  
Circular Cylinder ◽  
Oscillatory Flow ◽  
Reynolds Numbers ◽  
Number Range ◽  
High Reynolds Numbers ◽  
Reynolds Number Range ◽  
Fine Surface ◽  
High Reynolds

Measurements of pressures around a circular cylinder with fine surface roughness in planar oscillatory flow reveal considerable changes in drag and inertia coefficients over the Reynolds number range 2.5 × 105 to 7.5 × 105, and at Keulegan-Carpenter numbers between 5 and 25. In most respects, these results are shown to be compatible with previous measurements in planar oscillatory flow, and with previous measurements in which the same 0.5-m-dia cylinder was tested in waves.

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