In-line Oscillationof Structure with a Circular or Rectangular Section.

厚, 岡島; 澄明, 大津山; 稔朗, 永森; 智仁, 中野; 隆弘, 木綿

doi:10.1299/kikaib.65.2196

Cited by 15 publications

(7 citation statements)

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“…In addition, when α = 1, it is obviously found that our upwind finite element scheme matches the UTOPIA scheme proposed by Leonard . And also, see Reference for application of the upwind finite element approximations to a one‐dimensional problem to understand the relation between the discrete form and the differential form.…”

Section: Numerical Algorithm In Timesupporting

confidence: 65%

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Three‐dimensional computation for flow‐induced vibrations in in‐line and cross‐flow directions of a circular cylinder

Kondo

2011

Numerical Methods in Fluids

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SUMMARY We present numerical results for in‐line and cross‐flow vibrations of a circular cylinder, which is immersed in a uniform flow and is elastically supported by damper‐spring systems to compute vibrations of a rigid cylinder. In the case of a circular cylinder with a low Scruton number, it is well‐known that two types of self‐excited vibrations appear in the in‐line direction in the range of low reduced velocities. On the other hand, a cross‐flow vibration of the circular cylinder can be excited in the range of high reduced velocities. Therefore, we compute the flow‐induced vibrations of the circular cylinder in the wide range of the reduced velocities at low and high Scruton numbers and discuss about excitation mechanisms in the in‐line and cross‐flow directions. Copyright © 2011 John Wiley & Sons, Ltd.

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Section: Numerical Algorithm In Timesupporting

confidence: 65%

“…where each matrix in Equations (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) and (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) is given as follows:…”

Section: Time Integration For the Equations Of Motion Of A Circular Cmentioning

confidence: 99%

Three‐dimensional computation for flow‐induced vibrations in in‐line and cross‐flow directions of a circular cylinder

Kondo

2011

Numerical Methods in Fluids

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“…Païdoussis et al 2010). VIV of non-axisymmetric bodies potentially exposed to MIV, for instance, a cylinder with a square or rectangular cross-section, have also been analysed in several studies (Naudascher 1987;Obasaju, Ermshaus & Naudascher 1990;Okajima et al 1999;Nemes et al 2012;Zhao, Cheng & Zhou 2013). VIV naturally appear both in the direction normal to the current (cross-flow direction) and in the direction parallel to the current (in-line direction).…”

Section: Introductionmentioning

confidence: 99%

In-line flow-induced vibrations of a rotating cylinder

Bourguet

Jacono

2015

J. Fluid Mech.

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The flow-induced vibrations of an elastically mounted circular cylinder, free to oscillate in the direction parallel to the current and subjected to a forced rotation about its axis, are investigated by means of two-and three-dimensional numerical simulations, at a Reynolds number equal to 100 based on the cylinder diameter and inflow velocity. The cylinder is found to oscillate up to a rotation rate (ratio between the cylinder surface and inflow velocities) close to 2 (first vibration region), then the body and the flow are steady until a rotation rate close to 2.7 where a second vibration region begins. Each vibration region is characterized by a specific regime of response. In the first region, the vibration amplitude follows a bell-shaped evolution as a function of the reduced velocity (inverse of the oscillator natural frequency). The maximum vibration amplitudes, even though considerably augmented by the rotation relative to the non-rotating body case, remain lower than 0.1 cylinder diameters. Due to their trends as functions of the reduced velocity and to the fact that they develop under a condition of wake-body synchronization or lock-in, the responses of the rotating cylinder in this region are comparable to the vortex-induced vibrations previously described in the absence of rotation. The symmetry breaking due to the rotation is shown to directly impact the structure displacement and fluid force frequency contents. In the second region, the vibration amplitude tends to increase unboundedly with the reduced velocity. It may become very large, higher than 2.5 diameters in the parameter space under study. Such structural oscillations resemble the galloping responses reported for non-axisymmetric bodies. They are accompanied by a dramatic amplification of the fluid forces compared to the non-vibrating cylinder case. It is shown that body oscillation and flow unsteadiness remain synchronized and that a variety of wake topologies may be encountered in this vibration region. The low-frequency, large-amplitude responses are associated with novel asymmetric multi-vortex patterns, combining a pair and a triplet or a quartet of vortices per cycle. The flow is found to undergo three-dimensional transition in the second vibration region, with a limited influence on the system behaviour. It appears that the transition occurs for a substantially lower rotation rate than for a rigidly mounted cylinder.

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“…The deformation can be calculated by a moving boundary method. 11) One of the bench mark experiments for FIV in singlephase flow was reported by Okajima et al 12) A solid cylinder (diameter, 120 mm; length, 293 mm; material, expanded polystyrene) was supported by electromagnetic dampers at both ends and installed in an air flow (flow rate: 0.5-2 m/s). Displacement of the cylinder was measured by changing damping ratio and air flow velocity.…”

Section: Major Factors That Determine Structural Materials Problemsmentioning

confidence: 99%

Evaluation Methods for Corrosion Damage of Components in Cooling Systems of Nuclear Power Plants by Coupling Analysis of Corrosion and Flow Dynamics (I)

Naitoh¹,

Uchida²,

Koshizuka

et al. 2008

J. Nucl. Sci. Technol.

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Problems in major components and structural materials in nuclear power plants have often been caused by flow induced vibration and corrosion and their overlapping effects. In order to establish safe and reliable plant operation, future problems for structural materials should be predicted based on combined analyses of flow dynamics and corrosion and they should be mitigated before becoming serious issues for plant operation. Three approaches have been prepared for predicting future problems in structural materials: 1. Computer program packages for predicting future corrosion fatigue on structural materials, 2. Computer program packages for predicting future corrosion damage on structural materials, and 3. Computer program packages for predicting wall thinning caused by flow accelerated corrosion. General features of evaluation methods and their computer packages, technical innovations required for their development, and application plans for the developed approaches for plant operation are introduced in this paper.

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In-line Oscillationof Structure with a Circular or Rectangular Section.

Cited by 15 publications

References 0 publications

Three‐dimensional computation for flow‐induced vibrations in in‐line and cross‐flow directions of a circular cylinder

Three‐dimensional computation for flow‐induced vibrations in in‐line and cross‐flow directions of a circular cylinder

In-line flow-induced vibrations of a rotating cylinder

Evaluation Methods for Corrosion Damage of Components in Cooling Systems of Nuclear Power Plants by Coupling Analysis of Corrosion and Flow Dynamics (I)

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