Passive Control of Vortex-Induced Vibrations: An Overview

Kumar, Raghavan; Sohn, Chan-Hyun; Gowda, Bangalore

doi:10.2174/2212797610801010001

Cited by 88 publications

(15 citation statements)

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“…The phenomenon of flow-induced motion (FIM) can be frequently observed in many engineering structures such as long-spanned bridges [1], marine risers [2], power-transmission cables [3], etc. Vortex-induced vibration (VIV) is one of the most common FIM phenomena, which usually occurs due to the alternating shedding of vortices from either side of the bluff body [4].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Soft Galloping and Hard Galloping of Triangular Prisms

et al. 2017

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Abstract:The studies currently on soft galloping (SG) and hard galloping (HG) are scarce. In this study, SG and HG of spring-mounted triangular prisms in a water channel are investigated experimentally. A power take-off system (PTO), a spring system, additional weights, and different triangular prisms were used to achieve the variations in damping coefficient c, system stiffness K, oscillation mass m and section aspect ratios α, respectively. The present paper proves that the VIV (vortex-induced vibration) lower branch can be observed in the SG response. In SG response, VIV branches are incomplete while the galloping branch is complete, and galloping can be self-initiated only in the self-excited region. On the contrary, in HG response, VIV branches are complete, the galloping branch is incomplete, and galloping can only be initiated by external excitation at a velocity exceeding the critical velocity. As c and m increase, or K and α decrease, the oscillation mode of a triangular prism gradually transitions from SG to CG (critical galloping), and continues to HG. The amplitude in VIV branch is the main reason causing the onset of galloping in SG response. A critical damping coefficient c c , which is dependent on m, K and α, is proposed to predict the occurrences of SG, CG and HG. When c < c c , SG occurs; when c > c c , HG occurs; when c = c c , CG occurs.

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Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Soft Galloping and Hard Galloping of Triangular Prisms

et al. 2017

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“…Control of flow structure around a sphere for various active and passive methods was studied by Suryanarayana and Prabhu (2000), Suryanarayana and Meier (1995), Suryanarayana et al (1993), Ozgoren et al(2011bOzgoren et al( , 2011c, Kim and Durbin (1988), Kiya (1988), Owen and Bearman (1988), Mehta (1985) and further investigations cited therein [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Flow Characteristics of Different Sphere Geometries Under the Free Surface Effect

Özgören

Doğan

Okbaz

et al. 2013

EPJ Web of Conferences

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Abstract.Comparison of the experimental results of turbulent flow structures between a smooth sphere and a sphere with a vent hole, roughened, and o-ring is presented in the presence of a free-surface. Dye visualization and particle image velocimetry (PIV) techniques were performed to examine effects of passive control methods on the sphere wake for Reynolds number Re = 5000 based on the sphere diameter with a 42.5mm in an open water channel. Instantaneous and time-averaged flow patterns in the wake region of the sphere were examined from point of flow physics for the different sphere locations in the range of 0≤h/D ≤2.0 where h was the space between the top point of the sphere and the free surface. The ratio of ventilation hole to sphere diameter was 0.15, o-ring was located at 55 o with a 2 mm from front stagnation point of the sphere and roughened surface was formed by means of totally 410 circular holes with a 3 mm diameter and around 2 mm depth in an equilateral triangle arrangement. The flow characteristics of instantaneous velocity vectors, vorticity contours, time-averaged streamline patterns, Reynolds stress correlations and streamwise and cross-stream velocity fluctuations for both the smooth and passively controlled sphere were interpreted.

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“…Only the pertinent literature on passive control is discussed here. Conventional passive control strategies to subdue VIV based on add-on devices are discussed by Blevins (1990) and Kumar et al (2008). According to Zdravkovich (1981), these devices fall into three categories: (1) Surface protrusions, which affect separation lines and /or separated shear layers.…”

Section: Introductionmentioning

confidence: 99%

Suppression of vortex-induced vibrations of rigid circular cylinder on springs by localized surface roughness at 3×104≤Re≤1.2×105

Park¹,

Kumar

Bernitsas

2016

Ocean Engineering

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Suppression of Vortex-Induced Vibrations (VIV) of an elastically mounted circular cylinder in a steady flow is studied experimentally using localized surface roughness, called Passive Turbulence Control (PTC). PTC consists of two roughness strips with thickness on the order of the boundary layer thickness and placed parallel to the cylinder axis symmetrically with respect to the flow. The range of Reynolds number (3×10 4 ≤Re≤1.2×10 5 ) considered covers primarily the Transition to Shear Layer3, highlift, flow regime. For the smooth cylinder, the broad synchronization range and higher peak amplitude in the upper branch and unstable oscillations in the lower branch are characteristic of VIV at higher Reynolds numbers and distinctive from those of lower Reynolds numbers. From the PTC-cylinder results with systematic variation of the PTC location, one strong-suppression zone and two weak-suppression zones are identified based on the location of the PTC. These zones are part of the Map that established the relation between PTC and Flow-Induced Motions in previous work. In the strong suppression zone, reduction of 30%-80% is achieved while in the weak suppression zones reduction of less than 30% is achieved. Broad field-of-view flow visualization shows that smooth cylinder vortex structures change with PTC and between zones.

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Passive Control of Vortex-Induced Vibrations: An Overview

Cited by 88 publications

References 0 publications

Experimental Investigation on Soft Galloping and Hard Galloping of Triangular Prisms

Experimental Investigation on Soft Galloping and Hard Galloping of Triangular Prisms

Comparison of Flow Characteristics of Different Sphere Geometries Under the Free Surface Effect

Suppression of vortex-induced vibrations of rigid circular cylinder on springs by localized surface roughness at 3×104≤Re≤1.2×105

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