Low drag solutions for suppressing vortex-induced vibration of circular cylinders

Assi, Gustavo R. S.; Bearman, P. W.; Kitney, Neil

doi:10.1016/j.jfluidstructs.2008.11.002

Cited by 203 publications

(107 citation statements)

References 4 publications

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“…VIV may cause serious fatigue damageon the structures in offshore engineering. Much research work has been done on this typical fluid-structure interaction phenomenon throughout centuries, both numerically and experimentally, toward the understanding of the dynamic response features of VIV (Naudascher, 1987;Sarpkaya, 2004;Gabbai and Benaroya, 2005;Williamson and Govardhan, 2008;Wu et al, 2012b;Fan et al, 2015) and the VIV suppression (Zdravkovich, 1981;Bearman and Owen, 1998;Galvao et al, 2008;Assi et al, 2009;Wu et al, 2012a;Huera-Huarte, 2014;Gao et al, 2015aGao et al, , 2015bGao et al, , 2016.…”

Section: Introductionmentioning

confidence: 99%

Influences of the helical strake cross-section shape on vortex-induced vibrations suppression for a long flexible cylinder

Luan

Liu

et al. 2017

China Ocean Eng

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An experimental study on a bare flexible cylinder as well as cylinders fitted with two types of cross-sectioned helical strakes was carried out in a towing tank. The main purpose of this paper is to investigate the effects of strakes' crosssection on the vortex-induced vibrations (VIV) suppression of a flexible cylinder. The square-sectioned and roundsectioned helical strakes were selected in the experimental tests. The uniform current was generated by towing the cylinder models along the tank using a towing carriage. The Reynolds number was in the range of 800-16000. The strain responses were measured by the strain gages in cross-flow (CF) and in-line (IL) directions. A modal analysis method was adopted to obtain the displacement responses using the strain signals in different measurement positions. The comparison of the experimental results among the bare cylinder, square-sectioned straked cylinder and roundsectioned straked cylinder was performed. The helical strakes can effectively reduce the strain amplitude, displacement amplitude, response frequencies and dominant modes of a flexible cylinder excited by VIV. And the mean drag coefficients of straked cylinders were approximately consistent with each other. In addition, the squaresectioned and round-sectioned strakes nearly share the similar VIV reduction behaviors. Sometimes, the strakes with round-section represent more excellent effects on the VIV suppression of response frequency than those with squaresection.

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Section: Introductionmentioning

confidence: 99%

Influences of the helical strake cross-section shape on vortex-induced vibrations suppression for a long flexible cylinder

Luan

Liu

et al. 2017

China Ocean Eng

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“…Flow control usually involves two broad categories. For one, called passive control, the flow is modified without external energy input as helical strakes [19], fin [20], rope and bump [21], thick fairings [22] (p. 19377), splitter plates [23], guide foils [24] and so on. For the other, called active control, energy requires to be injected into the flow as momentum injections [25][26][27], moving-wall [28], synthetic jet actuators [29], suction and blowing [30][31][32][33][34] and so on.…”

Section: Governing Equationsmentioning

confidence: 99%

Investigations on the Effects of Vortex-Induced Vibration with Different Distributions of Lorentz Forces

et al. 2017

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Abstract:The control of vortex-induced vibration (VIV) in shear flow with different distributions of Lorentz force is numerically investigated based on the stream function-vorticity equations in the exponential-polar coordinates exerted on moving cylinder for Re = 150. The cylinder motion equation coupled with the fluid, including the mathematical expressions of the lift force coefficient C l , is derived. The initial and boundary conditions as well as the hydrodynamic forces on the surface of cylinder are also formulated. The Lorentz force applied to suppress the VIV has no relationship with the flow field, and involves two categories, i.e., the field Lorentz force and the wall Lorentz force. With the application of symmetrical Lorentz forces, the symmetric field Lorentz force can amplify the drag, suppress the flow separation, decrease the lift fluctuation, and then suppress the VIV while the wall Lorentz force decreases the drag only. With the application of asymmetrical Lorentz forces, besides the above-mentioned effects, the field Lorentz force can increase additional lift induced by shear flow, whereas the wall Lorentz force can counteract the additional lift, which is dominated on the total effect.

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“…The situation is of practical interest in many engineering applications as chimney stacks, long-span bridges, marine structures, tall buildings and towers etc. and has been steadily investigated by the researchers Bearman, [1,2,3,4,5]; Matsumato [6]; Williamson [7]; Williamson and Govardhan, [8,9]. In order to reduce or eliminate the adverse effects of vortex-induced vibrations (VIV), it is inevitably important to control the flow structure around the bluff body and/or alter the mechanical properties of the material used in terms of damping and natural frequency.…”

Section: Introductionmentioning

confidence: 99%

The effects of perforated cylinders on the vortex shedding on the suppression of a circular cylinder

et al. 2017

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Abstract. The aim of this study is the control of unsteady vortical flow occurred downstream of a circular cylinder located in shallow water flow using concentrically located outer perforated cylinder. The porosities, ȕ have been changed between 0.1 and 0.8 in the present study. The increments of porosity ȕ were taken as 0.05 in the range of 0.1 and 0.8 with a hole diameter of d=10 mm. The ratio of inner cylinder diameter to outer cylinder diameter, D i /D o was selected as 0.25, 0.3, 0.4, 0.5 and 0.6 the inner cylinder diameter is D i =50mm where the outer cylinder diameter is D d =100mm. Experiments were performed at a constant depth of the water level as h=50mm (half of the outer cylinder diameter). Free stream velocity was taken as U =100 mm/s corresponding to a Reynolds number of Re D o =10000 based on the outer cylinder diameter. It has been observed that the inner circular cylinder was highly affected by the existence of surrounding outer perforated cylinders. It is observed that the intensity of Reynolds shear stress correlating, is completely attenuated in the region both downstream of concentric cylinder and between the concentric cylinders. It is determined from the experiments that porosity, ȕ=0.55 is the most effective parameter for control of flow structure that is occurred from the inner cylinder.

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Low drag solutions for suppressing vortex-induced vibration of circular cylinders

Cited by 203 publications

References 4 publications

Influences of the helical strake cross-section shape on vortex-induced vibrations suppression for a long flexible cylinder

Influences of the helical strake cross-section shape on vortex-induced vibrations suppression for a long flexible cylinder

Investigations on the Effects of Vortex-Induced Vibration with Different Distributions of Lorentz Forces

The effects of perforated cylinders on the vortex shedding on the suppression of a circular cylinder

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