Response of a Circular Cylinder Fitted With Permeable Meshes Acting as VIV Suppressors

Experiments have been carried out on models of rigid circular cylinders fitted with three different types of permeable meshes to investigate their effectiveness in the suppression of vortex-induced vibrations (VIV). Measurements of amplitude of vibration and drag force are presented for models with low mass and damping which are free to respond in the cross-flow direction. Results for two meshes made of ropes and cylindrical tubes are compared with the VIV response of a bare cylinder and that of a known suppressor called the “ventilated trousers” (VT). All three meshes achieved an average 50% reduction of the peak response when compared with that of the bare cylinder. The sparse mesh configuration presented a similar behaviour to the VT, while the dense mesh produced considerable VIV response for an indefinitely long range of reduced velocity. All the three meshes have increased drag when compared with that of the bare cylinder. Reynolds number ranged from 5,000 to 25,000 and reduced velocity was varied between 2 and 15.

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Suppression of the Vortex-Induced Vibration of a Circular Cylinder With Permeable Meshes

Volume 1B, Symposia: Fluid Machinery; Fluid-Structure Interaction and Flow-Induced Noise in Industrial Applications; Flow Applications in Aerospace; Flow Manipulation and Active Control: Theory, Experiments and Implementation; Multiscale Methods for Multiphase Flow; Noninvasive Measurements in Single and Multiphase Flows ◽

10.1115/fedsm2014-22149 ◽

2014 ◽

Cited By ~ 1

Author(s):

Murilo M. Cicolin ◽

Cesar M. Freire ◽

Gustavo R. S. Assi

Keyword(s):

Reynolds Number ◽

Flow Direction ◽

Vortex Formation ◽

Cross Flow ◽

Circular Cylinders ◽

Vortex Induced Vibrations ◽

Image Velocimetry ◽

Different Types ◽

Cylindrical Tubes ◽

Low Mass

Experiments have been carried out on models of rigid circular cylinders fitted with three different types of permeable meshes to investigate their effectiveness in the suppression of vortex-induced vibrations (VIV). Measurements of the dynamic response are presented for models with low mass and damping which are free to respond in the cross-flow direction. Reynolds number ranged from 1,000 to 10,000 and reduced velocity was varied between 2 and 13. Also presented are measurements of the wake of static models with Particle Image Velocimetry (PIV) at Reynolds number equal to 4000. Results for two meshes made of ropes and cylindrical tubes are compared with the VIV response of a bare cylinder and that of a known suppressor called the “ventilated trousers” (VT). All three meshes achieved an average 50% reduction of the response when compared with that of the bare cylinder. The sparse mesh configuration presented a similar behaviour to the VT, while the dense mesh produced considerable VIV response for an indefinitely long range of reduced velocity. Visualisation of the flow by PIV around static cylinders revealed that all suppressors disrupt the vortex shedding and increase the formation length when compared to the bare cylinder. The VT mesh, which presented the best suppression, also presented the largest vortex formation length.

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The Effect of Rotational Friction on the Stability of Short-Tailed Fairings Suppressing Vortex-Induced Vibrations

Volume 7: CFD and VIV; Offshore Geotechnics ◽

10.1115/omae2011-49522 ◽

2011 ◽

Cited By ~ 5

Author(s):

Gustavo R. S. Assi ◽

Peter W. Bearman ◽

Michael A. Tognarelli ◽

Julia R. H. Rodrigues

Keyword(s):

Circular Cylinder ◽

Lift Force ◽

Flow Direction ◽

Fluid Dynamic ◽

Cross Flow ◽

Critical Limit ◽

Vortex Induced Vibrations ◽

Equivalent Length ◽

Low Mass ◽

The Stability

Experiments have been carried out on a free-to-rotate short-tail fairing fitted to a rigid length of circular cylinder to investigate the effect of rotational friction on the stability of this type of VIV suppressor. Measurements of the dynamic response are presented for models with low mass and damping which are free to respond in the cross-flow and streamwise directions. It is shown how VIV can be reduced if the fairing presents a rotational friction above a critical limit. In this configuration the fairing finds a stable position deflected from the flow direction and a steady lift force appears towards the side the fairing has deflected. The fluid-dynamic mechanism is very similar to that observed for a free-to-rotate splitter plate of equivalent length.

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VIV Suppression and Drag Reduction With Pivoted Control Plates on a Circular Cylinder

Volume 5: Materials Technology; CFD and VIV ◽

10.1115/omae2008-57609 ◽

2008 ◽

Cited By ~ 3

Author(s):

Gustavo R. S. Assi ◽

Peter W. Bearman

Keyword(s):

Reynolds Number ◽

Circular Cylinder ◽

Drag Reduction ◽

Flow Direction ◽

Cross Flow ◽

Two Dimensional ◽

Dimensional Control ◽

Helical Strakes ◽

Low Mass ◽

Viv Suppression

Experiments have been carried out on two-dimensional devices fitted to a rigid length of circular cylinder to investigate the efficiency of pivoting control plates as VIV suppressors. Measurements are presented for a circular cylinder with low mass and damping which is free to respond in the cross-flow direction. It is shown how vortex-induced vibration can be practically eliminated by using free to rotate, two-dimensional control plates. Unlike helical strakes, the devices achieve VIV suppression with drag reduction. The device producing the largest drag reduction was found to have a drag coefficient equal to about 70% of that for a plain cylinder at the same Reynolds number.

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Vortex-Induced Vibrations of a Cylinder at Subcritical Reynolds Number

ASME 2011 Pressure Vessels and Piping Conference: Volume 4 ◽

10.1115/pvp2011-57392 ◽

2011 ◽

Author(s):

Yoann Jus ◽

Elisabeth Longatte ◽

Jean-Camille Chassaing ◽

Pierre Sagaut

Keyword(s):

Reynolds Number ◽

Numerical Simulations ◽

Numerical Study ◽

Damping Ratio ◽

Experimental Studies ◽

Cross Flow ◽

Physical Analysis ◽

Arbitrary Lagrangian Eulerian ◽

Vortex Induced Vibrations ◽

Low Mass

The present work focusses on the numerical study of Vortex-Induced Vibrations (VIV) of an elastically mounted cylinder in a cross flow at moderate Reynolds numbers. Low mass-damping experimental studies show that the dynamic behavior of the cylinder exhibits a three-branch response model, depending on the range of the reduced velocity. However, few numerical simulations deal with accurate computations of the VIV amplitudes at the lock-in upper branch of the bifurcation diagram. In this work, the dynamic response of the cylinder is investigated by means of three-dimensional Large Eddy Simulation (LES). An Arbitrary Lagrangian Eulerian framework is employed to account for fluid solid interface boundary motion and grid deformation. Numerous numerical simulations are performed at a Reynolds number of 3900 for both no damping and low-mass damping ratio and various reduced velocities. A detailed physical analysis is conducted to show how the present methodology is able to capture the different VIV responses.

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VIV and WIV Suppression With Parallel Control Plates on a Pair of Circular Cylinders in Tandem

Volume 5: Polar and Arctic Sciences and Technology; CFD and VIV ◽

10.1115/omae2009-79081 ◽

2009 ◽

Cited By ~ 1

Author(s):

Gustavo R. S. Assi ◽

Peter W. Bearman

Keyword(s):

Circular Cylinder ◽

Drag Reduction ◽

Flow Direction ◽

Cross Flow ◽

Offshore Structures ◽

Circular Cylinders ◽

Parallel Plates ◽

Tandem Cylinders ◽

Helical Strakes ◽

Viv Suppression

Experiments have been carried out on two-dimensional devices fitted to a rigid length of circular cylinder to investigate the efficiency of pivoting parallel plates as wake-induced vibration suppressors. Measurements are presented for a circular cylinder with low mass and damping which is free to respond in the cross-flow direction. It is shown how VIV and WIV can be practically eliminated by using free to rotate parallel plates on a pair of tandem cylinders. Unlike helical strakes, the device achieves VIV suppression with 33% drag reduction when compare to a pair of fixed tandem cylinders at the same Reynolds number. These results prove that suppressors based on parallel plates have great potential to suppress VIV and WIV of offshore structures with considerable drag reduction.

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The Numerical Research of Two-Degrees-of-Freedom Vortex-Induced Vibrations of Circular Cylinders

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.204-208.4598 ◽

2012 ◽

Vol 204-208 ◽

pp. 4598-4601

Author(s):

Jie Li Fan ◽

Wei Ping Huang

Keyword(s):

Degrees Of Freedom ◽

Amplitude Ratio ◽

Flow Direction ◽

Cross Flow ◽

Circular Cylinders ◽

Two Degrees Of Freedom ◽

Line Frequency ◽

Ansys Cfx ◽

Vortex Induced Vibrations ◽

Lock In

The two-degrees-of-freedom of vortex-induced vibration of circular cylinders is numerically simulated with the software ANSYS/CFX. The VIV characteristic, in the two different conditions (A/D=0.07 and A/D=1.0), is analyzed. When A/D is around 0.07, the amplitude ratio of the cylinder’s VIV between in-line and cross-flow direction in the lock-in is lower than that in the lock-out. The in-line frequency is twice of that in cross-flow direction in the lock-out, but in the lock-in, it is the same as that in cross-flow direction and the same as that of lift force. When A/D is around 1.0, the amplitude ratio of the VIV between in-line and cross-flow in the lock-in is obviously larger than that in the lock-out. Both in the lock-in and in the lock-out, the in-line frequency is twice of that in cross-flow direction.

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Experimental Evaluation of Pure In-Line Vortex Induced Vibration (VIVx) of Low Mass-Damping Ratio Cylinder

Volume 2: CFD and VIV ◽

10.1115/omae2016-54374 ◽

2016 ◽

Author(s):

Mohammad Mobasher Amini ◽

Antonio Carlos Fernandes

Keyword(s):

Reynolds Number ◽

Circular Cylinder ◽

Damping Ratio ◽

Cross Flow ◽

Current Channel ◽

Number Range ◽

Vortex Induced Vibration ◽

Numerical Studies ◽

Lower Amplitude ◽

Low Mass

Numerous experimental and numerical studies have been carried out to better understand and to improve prediction of cylinder VIV (vortex Induced Vibration) phenomenon. The behavior of cylinder due to in-line vibration (VIVx) has been neglected in the earlier studies because of its lower amplitude in comparison with cross flow vibration (VIVy). However, some researchers have studied VIVx in 2DOF along with VIVy. Recent investigations show that response amplitude of structure caused by VIVx is large enough to bring it to consideration. This study focuses on understanding the origin and prediction of VIVx amplitude exclusively in 1DOF and subcritical flow regime. The experiments were performed in current channel on bare circular cylinder with low mass-damping ratio in Reynolds number range Re = 10000 ∼ 45000.

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Vortex-Induced Vibration of Two Side-by-Side Cylinders With a Small Gap in Uniform Flow

Volume 2: Prof. Carl Martin Larsen and Dr. Owen Oakley Honoring Symposia on CFD and VIV ◽

10.1115/omae2017-61178 ◽

2017 ◽

Cited By ~ 1

Author(s):

Adnan Munir ◽

Ming Zhao ◽

Helen Wu

Keyword(s):

Stokes Equations ◽

Flow Direction ◽

Three Dimensional ◽

Cross Flow ◽

Circular Cylinders ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Gap Ratio ◽

Vortex Induced Vibrations ◽

Lock In

Vortex-induced vibrations of two elastically mounted and rigidly coupled circular cylinders in side-by-side arrangement in steady flow are investigated numerically. The vibration of the cylinders is limited to the cross-flow direction only. The three-dimensional Navier-Stokes equations are solved using the Petrov-Galerkin Finite element method and the equation of motion is solved using the fourth order Runge Kutta method. It is well known that when the gap between two stationary side-by-side cylinders is very small, the flow between the two cylinders is biased towards one cylinder and the lift force on each cylinder is significantly smaller than that of an isolated single cylinder. The aim of this study is to investigate the effect of a small gap ratio of 0.5 between the two cylinders on the lock-in regime and the amplitude of the vibration of two side-by-side cylinders in a fluid flow. Simulations are carried out for a constant mass ratio of 2, a constant Reynolds number of 1000 and a range of reduced velocities. It is found that in the lock-in range of the reduced velocity, the two cylinders vibrate about their balance position with high amplitudes. Outside the lock-in regime the flow from the gap becomes biased towards one cylinder, which is similar to that from the gap between stationary cylinders.

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Flow Induced Oscillation of a Set-In Circular Cylinder

Volume 15: Sound, Vibration and Design ◽

10.1115/imece2009-12462 ◽

2009 ◽

Author(s):

F. Oviedo-Tolentino ◽

R. Romero-Mendez ◽

A. Hernandez-Guerrero ◽

J. M. Luna

Keyword(s):

Reynolds Number ◽

Circular Cylinder ◽

Vortex Shedding ◽

Flow Direction ◽

Flow Behavior ◽

Cross Flow ◽

Close Relation ◽

Structure Interaction ◽

Visualization Techniques ◽

Flow Experiments

This work studies the fluid-structure interaction of a set-in, large aspect-ratio circular cylinder in cantilever subjected to a cross flow. Experiments were conducted in a water tunnel and observations were obtained using flow visualization techniques and direct observation of the deflection of the cylinder. The flow behavior was observed using dye injection. The experiments show that the dominant vibration of the cylinder is transversal to the flow direction, and that the first mode of vibration of the cylinder appears at a particular Reynolds number, which is a function of the mechanical properties of the cylinder. The deflection stops when the Reynolds number is increased. The peak deflection and frequency of oscillation, as a function of the Reynolds number, were also determined. The analysis shows a close relation between the frequency of oscillation and the frequency of appearance of a vortex shedding. For large deflections of the cylinder the flow structure is modified substantially, and the frequency at which vortex appears is different to the frequency that occurs for fixed cylinders.

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