A Simple Fluid/Structure and Structure/Structure Interaction Problem in Flow-Induced Vibration

2002 ◽  
Author(s):  
Y. Liu ◽  
R. M. C. So ◽  
Y. L. Lau
Keyword(s):  
Vortex Formation ◽  
Cross Flow ◽  
Reynolds Numbers ◽  
Quantitative Agreement ◽  
Splitter Plate ◽  
Flow Induced Vibration ◽  
Vibration Behavior ◽  
Interaction Problem ◽  
Plate System ◽  
Good Agreement

It is known that a splitter plate can moderate the vortex formation behind a cylinder, and consequently the vibration behavior of the cylinder and the plate. This paper uses the standard k-ε model and a modified wall function to simulate the flow-induced vibration of a 2D cylinder-plate system in a cross flow. Good agreement between available measurements and calculations is obtained for a single cylinder in a cross flow at Reynolds numbers up to 105. The flow-induced vibration of a cylinder-plate system in a cross flow is attempted using the same numerical method. It is possible to replicate the vibration behavior for the cylinder and the splitter plate, even though quantitative agreement with measurements is not obtained.

Effects of sound on separated flows

1969 ◽  
Vol 37 (2) ◽  
pp. 265-287 ◽  
Author(s):  
Jon A. Peterka ◽  
Peter D. Richardson
Keyword(s):  
Heat Transfer ◽  
Shear Layer ◽  
Vortex Breakdown ◽  
Vortex Formation ◽  
Cross Flow ◽  
Sound Field ◽  
Reynolds Numbers ◽  
Shear Layers ◽  
Formation Region ◽  
Region Length

Measurements of flow and fluctuating heat transfer were made for a circular cylinder in cross-flow with a transverse standing sound field imposed simultaneously. Reynolds numbers were of the order of 104, known to be in the disturbance-sensitive range, and sound intensities were as large as 140 db. The frequencies of the sound field were of the order of the disturbance frequency in the separated shear layers, reported first by Bloor.With a sound field having its frequency matched sufficiently closely to that occurring naturally in the shear layer, the growth of the instability is enhanced with the processes of vortex fusion and possibly vortex breakdown being detectable. At the same time, the vortex street frequency is only very weakly affected, although the vortex formation region length is reduced when the instability in the shear layer is enhanced. It is suggested that the discretization of vorticity in the shear layers is one factor significant in reducing the formation length. Heat transfer at the rear of the cylinder fluctuates at frequencies centred on the shedding frequency. The fluctuation level increases as the formation region shortens.

Numerical Simulation of Vortex Shedding Past a Circular Cylinder in a Cross-Flow at Low Reynolds Number With Finite Volume Technique: Part 2 — Flow-Induced Vibration

2007 ◽  
Author(s):  
Antoine Placzek ◽  
Jean-Franc¸ois Sigrist ◽  
Aziz Hamdouni
Keyword(s):  
Circular Cylinder ◽  
Vortex Shedding ◽  
Time Integration ◽  
Cross Flow ◽  
Forced Oscillations ◽  
Turbulent Regime ◽  
Flow Induced Vibration ◽  
Coupling Procedure ◽  
Vortex Shedding Modes ◽  
Good Agreement

This paper is the sequel of the work exposed in a companion publication dealing with forced oscillations of a circular cylinder in a cross-flow. In the present study, oscillations of the cylinder are now directly induced by the vortex shedding process in the wake and therefore, the former model used for forced oscillations has been modified to take into account the effects of the flow in order to predict the displacement of the cylinder. The time integration of the cylinder motion is performed with an explicit staggered algorithm whose numerical damping is low. In the first part of the paper, the performances of the coupling procedure are evaluated in the case of a cylinder oscillating in a confined configuration for a viscous flow. Amplitude and frequency responses of the cylinder in a cross-flow are then investigated for different reduced velocities U* ranging from 3 to about 15. The results show a very good agreement at Re = 100 and the vortex shedding modes have also been related to the frequency response observed. Finally, some perspectives for further simulations in the turbulent regime (at Re = 1000) with structural damping are presented.

Flow-induced vibration of two elastically mounted tandem cylinders in cross-flow at subcritical Reynolds numbers

2019 ◽  
Vol 173 ◽  
pp. 375-387 ◽  
Author(s):  
Wanhai Xu ◽  
Chunning Ji ◽  
Hai Sun ◽  
Wenjun Ding ◽  
Michael M. Bernitsas
Keyword(s):  
Cross Flow ◽  
Reynolds Numbers ◽  
Flow Induced Vibration ◽  
Tandem Cylinders

Cross-Flow Past a Pair of Staggered Cylinders With the Upstream Cylinder Subjected to a Transverse Harmonic Oscillation

2002 ◽  
Author(s):  
Stuart J. Price ◽  
Srikanth Krishnamoorthy ◽  
Michael P. Pai¨doussis
Keyword(s):  
Flow Direction ◽  
Vortex Formation ◽  
Cross Flow ◽  
Harmonic Oscillation ◽  
Reynolds Numbers ◽  
Circular Cylinders ◽  
Flow Past ◽  
The Mean ◽  
Lock In ◽  
Hot Film

An experimental investigation of the cross-flow past a pair of staggered circular cylinders, with the downstream cylinder subject to forced harmonic oscillation transverse to the flow direction, is presented in this paper. In particular, flow-visualization of the wakeformation region and hot-film measurements of the wake spectra are reported. Experiments were conducted in a water tunnel for Reynolds numbers, based on upstream velocity, U, and cylinder diameter, D, in the range 1440 ≤ Re ≤ 1680. The longitudinal separation between cylinder centers is L/D = 2.0, with a transverse separation (for the mean position of the upstream cylinder) of T/D = 0.17. As shown in an earlier study, depending on the actual position of the upstream cylinder in its oscillation cycle, this configuration straddles the shear-layer reattachment and induced separation regimes. The results show that the oscillation of the upstream cylinder causes considerable modification of the flow patterns and regimes compared to what is obtained when the cylinder is fixed. In particular, depending on the frequency of oscillation of the upstream cylinder, sub- and superharmonic resonances are obtained between the vortex formation frequency and oscillation frequency, as well as the usual fundamental lock-in. These resonances and accompanying wake regimes are examined in detail in this paper.

Cross-Flow Past a Pair of Staggered Cylinders With the Upstream Cylinder Subjected to a Transverse Harmonic Oscillation

2006 ◽  
Author(s):  
Stuart J. Price ◽  
Michael P. Pai¨doussis ◽  
Srikanth Krishnamoorthy
Keyword(s):  
Flow Direction ◽  
Vortex Formation ◽  
Cross Flow ◽  
Harmonic Oscillation ◽  
Reynolds Numbers ◽  
Circular Cylinders ◽  
Vortex Pairing ◽  
Flow Past ◽  
Lock In ◽  
Hot Film

The results of an experimental investigation are presented for the cross-flow past a pair of staggered circular cylinders, with the upstream cylinder being subject to forced harmonic oscillation transverse to the flow direction. Flow-visualization of the wake-formation region and hot-film measurements of the wake spectra are reported. Experiments were conducted in a water tunnel for Reynolds numbers, based on upstream velocity, U, and cylinder diameter, D, in the range 1440 ≤ Re ≤ 1680. Results are presented for the case where the longitudinal separation between cylinder centres (for the mean position of the upstream cylinder) is L/D = 2.0, with the transverse separation being T/D = 1.0. As shown by Sumner et al. [1] this configuration corresponds to either the gap vortex pairing and enveloping or gap vortex pairing, splitting and enveloping regimes. The results show that the oscillation of the upstream cylinder causes considerable modification of the flow patterns and regimes compared to what is obtained when the cylinder is fixed. In particular, depending on the frequency of oscillation of the upstream cylinder, sub- and super-harmonic resonances are obtained between the vortex formation frequency and oscillation frequency, as well as the usual fundamental lock-in. These resonances and accompanying wake regimes are examined in detail in the paper.

Differences in Predicted Flow-Induced Vibration of Submarine Pipelines Considering Cross-Flow and Inline Oscillations and its Influence in Fatigue-Life

2016 ◽  
Author(s):  
Anthony Dominguez ◽  
Armando Blanco ◽  
Euro Casanova ◽  
Nelson Loaiza ◽  
Janneth García
Keyword(s):  
Fluid Flow ◽  
Cross Flow ◽  
Reynolds Numbers ◽  
Flow Induced Vibration ◽  
Fluid Flow Velocity ◽  
Ansys Cfx ◽  
Vortex Induced Vibrations ◽  
Flow Oscillations ◽  
Lift And Drag ◽  
External Forces

In offshore facilities, the most widely spread way to transport fluids in relatively short distances is through submarine pipelines. These structures are subject to internal and external forces. Nowadays, most of the proposed models to study submarine pipelines subjected to vortex induced vibrations feature a circular cylinder, submitted to a cross-flow, and are able to display oscillations in just the transverse direction to the fluid flow velocity. In this paper three different models that consider a two-dimensional fluid flow around a pipeline were studied via ANSYS CFX®, for Reynolds numbers between 100 and 700, with the purpose of determining the limitations of the 1-DOF models based on the Strouhal number and lift and drag coefficients and account its influence in fatigue lifespan. These models consisted of a static cylinder — i.e. no oscillations —, a cylinder with 1-DOF — i.e. cross-flow oscillations — and a cylinder with 2-DOF — i.e. cross-flow and inline oscillations —. It was found that, although fluid flow Reynolds numbers were very small as to make the submarine pipeline models fall within the finite-life region, a 1-DOF model is accurate enough to predict fatigue lifespan, since it presents respect to the 2-DOF model little deviation in the chosen comparison parameters.

An Investigation of the Corner Secondary Flows Generated in Planar Nozzles

1974 ◽  
Vol 96 (3) ◽  
pp. 234-245
Author(s):  
W. B. Wagner ◽  
J. A. Owczarek
Keyword(s):  
Boundary Layer ◽  
Total Pressure ◽  
Cross Flow ◽  
Reynolds Numbers ◽  
Flow Speed ◽  
Secondary Flows ◽  
Experimental Results ◽  
Average Flow ◽  
Aspect Ratios ◽  
Good Agreement

An experimental study was made of the total pressure distribution in the corner secondary flow generated in two planar nozzles having different contours. Also, an analysis was made of the extent of the sidewall boundary layer migration caused by the cross flow and of its accumulation in the corner between the sidewall and horizontal nozzle walls at exits of planar nozzles. A comparison of the calculated and experimental results was made. Reasonably good agreement was found between the analytical and experimental results. The Reynolds numbers considered in this study, based on the average flow speed at nozzle exits and on the nozzle widths, were 5000, 10,000, and 20,000. The nozzle aspect ratios were 4 and 2.

TRANSONIC CROSS FLOW (M∞ = 0.8) OVER A CIRCULAR CYLINDER AT HIGH REYNOLDS NUMBERS

2012 ◽  
Vol 43 (5) ◽  
pp. 589-613
Author(s):  
Vyacheslav Antonovich Bashkin ◽  
Ivan Vladimirovich Egorov ◽  
Ivan Valeryevich Ezhov ◽  
Sergey Vladimirovich Utyuzhnikov
Keyword(s):  
Circular Cylinder ◽  
Cross Flow ◽  
Reynolds Numbers ◽  
High Reynolds Numbers ◽  
High Reynolds

Simulation of Unsteady Flow Around a Cylinder

2015 ◽  
Vol 3 (2) ◽  
pp. 28-49
Author(s):  
Ridha Alwan Ahmed
Keyword(s):  
Stokes Equations ◽  
Lift Coefficient ◽  
Reynolds Numbers ◽  
Mean Value ◽  
Navier Stokes ◽  
Cylinder Surface ◽  
Navier Stokes Equations ◽  
Flow Around A Cylinder ◽  
Numerical Grid ◽  
Good Agreement

       In this paper, the phenomena of vortex shedding from the circular cylinder surface has been studied at several Reynolds Numbers (40≤Re≤ 300).The 2D, unsteady, incompressible, Laminar flow, continuity and Navier Stokes equations have been solved numerically by using CFD Package FLUENT. In this package PISO algorithm is used in the pressure-velocity coupling.        The numerical grid is generated by using Gambit program. The velocity and pressure fields are obtained upstream and downstream of the cylinder at each time and it is also calculated the mean value of drag coefficient and value of lift coefficient .The results showed that the flow is strongly unsteady and unsymmetrical at Re>60. The results have been compared with the available experiments and a good agreement has been found between them

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