Forced Oscillation of a Circular Cylinder

2010 ◽  
Author(s):  
Bruno G. Camargo ◽  
Marcelo A. Vitola ◽  
Juan B. V. Wanderley ◽  
Sergio H. Sphaier ◽  
Carlos A. Levi
Keyword(s):  
Circular Cylinder ◽  
Forced Vibration ◽  
Amplitude Ratio ◽  
Practical Interest ◽  
Numerical Results ◽  
The Body ◽  
Curvilinear Coordinates ◽  
Mean Flow ◽  
Conservative Scheme ◽  
Lock In

Circular structures are frequently found in offshore industrial application, such as risers, umbilicals, spars, and TLP platforms. Theses structures are frequently subjected to vortex induced vibration. Sometimes, they are also subjected to forced vibration. In the present paper, the forced vibration of a circular cylinder is investigated by the numerical solution of the Reynolds Average Navier-Stokes (RANS) equations. An upwind and Total Variation Diminishing (TVD) conservative scheme is used to solve the governing equations written in curvilinear coordinates. The k–ε turbulence model is used to simulate the turbulent flow in the wake of the body, when necessary. The cylinder is forced to oscillate only in the transverse direction of the mean flow with low Reynolds number and low amplitude ratio. The numerical results of the lift and drag coefficients were compared with numerical data obtained from Benevenutti and Silvestrini [1] and Meneghini and Bearman [2] to validate the code for forced vibration. The numerical results indicate that the implemented code is able to reproduce the experimental data capturing quite well the lock-in boundary, and results of practical interest are obtained, such as mean drag, RMS lift and lock-in range and.

A Numerical Investigation of the Hysteresis Effect on Vortex Induced Vibration on an Elastically Mounted Rigid Cylinder

2009 ◽  
Author(s):  
Juan B. V. Wanderley ◽  
Sergio H. Sphaier ◽  
Carlos Levi
Keyword(s):  
Vortex Shedding ◽  
Stokes Equations ◽  
Lift Coefficient ◽  
Practical Interest ◽  
Numerical Results ◽  
Hysteresis Effect ◽  
The Body ◽  
Curvilinear Coordinates ◽  
Vortex Induced Vibration ◽  
Conservative Scheme

The hysteresis effect on the vortex induced vibration (VIV) on a circular cylinder is investigated by the numerical solution of the Reynolds average Navier-Stokes equations. An upwind and Total Variation Diminishing (TVD) conservative scheme is used to solve the governing equations written in curvilinear coordinates and the k-ε turbulence model is used to simulate the turbulent flow in the wake of the body. The cylinder is supported by a spring and a damper and free to vibrate in the transverse direction. In previous work, numerical results for the amplitude of oscillation and vortex shedding frequency were compared to experimental data obtained from the literature to validate the code for VIV simulations. In the present work, results of practical interest are presented for the power absorbed by the system, phase angle, amplitude, frequency, and lift coefficient. The numerical results indicate that the hysteresis effect is observed only when the frequency of vortex shedding gets closer to the natural frequency of the structure in air.

A Two-Dimensional Numerical Investigation of the Hysteresis Effect on Vortex Induced Vibration on an Elastically Mounted Rigid Cylinder

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Juan B. V. Wanderley ◽  
Sergio H. Sphaier ◽  
Carlos Levi
Keyword(s):  
Vortex Shedding ◽  
Stokes Equations ◽  
Lift Coefficient ◽  
Practical Interest ◽  
Numerical Results ◽  
Hysteresis Effect ◽  
The Body ◽  
Curvilinear Coordinates ◽  
Two Dimensional ◽  
Vortex Induced Vibration

The hysteresis effect on the vortex induced vibration (VIV) on a circular cylinder is investigated by the numerical solution of the two-dimensional Reynolds averaged Navier-Stokes equations. An upwind and total variation diminishing (TVD) conservative scheme is used to solve the governing equations written in curvilinear coordinates and the k-ɛ turbulence model is used to simulate the turbulent flow in the wake of the body. The cylinder is supported by a spring and a damper and free to vibrate in the transverse direction. In previous work, numerical results for the amplitude of oscillation and vortex shedding frequency were compared to experimental data obtained from the literature to validate the code for VIV simulations. In the present work, results of practical interest are presented for the power absorbed by the system, phase angle, amplitude, frequency, and lift coefficient. The numerical results indicate that the hysteresis effect is observed only when the frequency of vortex shedding gets closer to the natural frequency of the structure in air.

Simulation of Low-Reynolds Number Flow Around a Circular Cylinder Following a Slender Elliptical Path

2013 ◽  
Author(s):  
László Baranyi
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Amplitude Ratio ◽  
Oscillation Amplitude ◽  
Base Pressure ◽  
Reynolds Number Flow ◽  
Two Dimensional Flow ◽  
Number Flow ◽  
Low Reynolds ◽  
Lock In

Two-dimensional flow around a circular cylinder forced to follow an elliptical path at low Reynolds numbers is investigated numerically using a thoroughly tested in-house code based on the finite difference method. Time-mean (TM) and rms values of lift, drag and base pressure coefficients are investigated within the lock-in region against the transverse oscillation amplitude for Reynolds number Re = 150 at frequency ratios of 0.8, 0.9 and 1.0 while the ratio of in-line and transverse cylinder oscillation amplitudes is kept at six different values yielding slender elliptical cylinder paths. The objective of the paper is to investigate the effect of the shape of the path, or amplitude ratio, on force coefficients. Findings show that for the cases investigated the rms of lift and TM of drag and base pressure are hardly affected by the amplitude ratio, while its effects are pronounced on the TM of lift and rms of drag and base pressure.

A Numerical Investigation of the Response of an Elastically Mounted Rigid Cylinder With Two Degrees of Freedom

2010 ◽  
Author(s):  
Bruno C. Ferreira ◽  
Marcelo A. Vitola ◽  
Juan B. V. Wanderley ◽  
Sergio H. Sphaier ◽  
Carlos A. Levi
Keyword(s):  
Experimental Data ◽  
Phase Angle ◽  
Degrees Of Freedom ◽  
Stokes Equations ◽  
Lift Coefficient ◽  
The Body ◽  
Curvilinear Coordinates ◽  
Two Degrees Of Freedom ◽  
Conservative Scheme ◽  
Rigid Cylinder

The vortex induced vibration (VIV) on a circular cylinder is investigated by the numerical solution of the Reynolds average Navier-Stokes equations. An upwind and Total Variation Diminishing (TVD) conservative scheme is used to solve the governing equations written in curvilinear coordinates and the k–ε turbulence model is used to simulate the turbulent flow in the wake of the body. The cylinder is supported by a spring and a damper and free to vibrate in the transverse and in-line directions. In previous work, numerical results for the amplitude of oscillation, vortex shedding frequency, and phase angle between lift and displacement were compared to experimental data obtained from Khalak and Williamson (1996) to validate the code for VIV simulations in the transverse direction. In the present work, results are obtained for phase angle, amplitude, frequency, and lift coefficient and compared to experimental data from Jauvtis and Williamson (2003) for an elastically mounted rigid cylinder with two degrees of freedom. Differences in the amplitude of oscillation between experimental and numerical data were observed for both direction. It seems that the fluid flow memory effect is an important aspect that should be taken in consideration on numerical simulation to reproduce the experimental results for VIV with 2DOF as pointed out by Moe and Wu [1].

Reynolds Number Effect on Vortex-Induced Vibration on a Two-Dimensional Circular Cylinder With Low Mass-Damping Parameter

2011 ◽  
Author(s):  
Juan B. V. Wanderley ◽  
Luiz F. Soares ◽  
Marcelo Vitola ◽  
Sergio H. Sphaier ◽  
Carlos Levi
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Lift Coefficient ◽  
The Body ◽  
Response Amplitude ◽  
Curvilinear Coordinates ◽  
Number Range ◽  
Vortex Induced Vibration ◽  
Damping Parameter ◽  
Low Mass

The vortex induced vibration (VIV) on a circular cylinder with low mass-damping parameter and low Reynolds number is investigated numerically as basis for applications on dynamics of risers used in the offshore oil and gas industry and as a first step before tackling the harder high Reynolds number problem. The cylinder is supported by a spring and a damper and free to vibrate in the transverse direction. The numerical solution of the Reynolds average Navier-Stokes equations written in curvilinear coordinates is obtained using an upwind and Total Variation Diminishing conservative scheme and the k-ε turbulence model is used to simulate the turbulent flow in the wake of the body. Results were obtained for the phase angle, response amplitude, frequency, and lift coefficient for a variation of reduced velocity from 2 to 12 and three different proportional variations of Reynolds number, 2000–6000, 2000–12000, and 2000–24000. The numerical results indicate the strong effect of the Reynolds number range on the response amplitude, lift coefficient, and frequency of oscillation for a low mass-damping parameter.

Pressure-fluctuation measurements on an oscillating circular cylinder

1979 ◽  
Vol 91 (4) ◽  
pp. 661-677 ◽  
Author(s):  
P. W. Bearman ◽  
I. G. Currie
Keyword(s):  
Circular Cylinder ◽  
Flow Model ◽  
Free Stream ◽  
Pressure Fluctuations ◽  
The Body ◽  
The Mean ◽  
Simple Potential ◽  
Lock In ◽  
Potential Flow Model ◽  
Good Agreement

Measurements are presented of the fluctuating pressure recorded at a point 90° from the mean position of the forward stagnation point on a circular cylinder oscillating in a water flow. The aspect ratio of the cylinder was 9·5 and the turbulence level in the free-stream was 5·5%. The cylinder Reynolds number was 2·4 × 104 and the cylinder was forced to oscillate transverse to the main flow at amplitudes up to 1·33 cylinder diameters. The reduced velocity was varied over the range 3–18 and the experiments spanned the vortex-shedding lock-in range. Measurements of phase difference between pressure and displacement show that the maximum out-of-phase lift force occurs at an amplitude of about half a diameter. Good agreement is found between measurements on forced and freely oscillating cylinders. A simple potential-flow model gives reasonable predictions of the pressure fluctuations at the body frequency and at twice the body frequency at reduced velocities away from lock-in.

Lock-in in forced vibration of a circular cylinder

2016 ◽  
Vol 28 (11) ◽  
pp. 113605 ◽  
Author(s):  
Samvit Kumar ◽  
Navrose ◽  
Sanjay Mittal
Keyword(s):  
Circular Cylinder ◽  
Forced Vibration ◽  
Lock In

Analyzing Oscillating Input Flow around a Circular Cylinder

2011 ◽  
Vol 110-116 ◽  
pp. 644-652
Author(s):  
Behzad Ghadiri Dehkordi ◽  
Ali Mehrabadir
Keyword(s):  
Fluid Flow ◽  
Circular Cylinder ◽  
Drag Coefficient ◽  
Transverse Velocity ◽  
Lift Coefficient ◽  
Numerical Results ◽  
Input Flow ◽  
2D Simulation ◽  
Input Section ◽  
Lock In

2D fluid flow around a circular cylinder is numerically studied where the input flow is oscillating at different values of forcing frequency. The input section of domain has constant horizontal velocity except a region in the middle of this section which has an oscillating transverse velocity. The uniform fluid flow around an oscillating circular cylinder is also studied. The results are obtained for these two cases and compared with other experimental and numerical results. A comparison of the numerical results with the experimental data indicates that the 2D simulation has excellent agreement with literature. The effect of oscillation on the flow field, wake pattern and drag coefficient has been studied. The results show that the lift coefficient diagram is pure sinusoidal for forcing frequency f=0.85 and is lied in the lock-in zone. The mean drag coefficient has a maximum value in this forcing frequency.

An experimental study of pressure fluctuations on fixed and oscillating square-section cylinders

1982 ◽  
Vol 119 ◽  
pp. 297-321 ◽  
Author(s):  
P. W. Bearman ◽  
E. D. Obasaju
Keyword(s):  
Experimental Study ◽  
Circular Cylinder ◽  
Drag Coefficient ◽  
Vortex Shedding ◽  
Pressure Fluctuations ◽  
The Body ◽  
Front Face ◽  
Side Face ◽  
Lock In ◽  
Fixed Cylinder

Measurements are presented of the pressure fluctuations acting on a stationary squaresection cylinder, with the front face normal to the flow, and one forced to oscillate, transverse to a flow, at amplitudes up to 25% of the length of a side. The range of reduced velocities investigated, 4–13, includes the vortex lock-in regime. At lock-in the amplification of the coefficient of fluctuating lift is found to be much less than that found for a circular cylinder. The variation of the phase angle, between lift and displacement, is also different from that measured on a circular cylinder, and vortex-induced oscillations are possible only at the high-reduced-velocity end of the lock-in range. At reduced velocities sufficiently far below lock-in the natural vortex-shedding mode is suppressed and vortices are found to form over the side faces at the body frequency. Intermittent reattachment occurs over the side faces and, for an amplitude of oscillation equal to 10% of the length of a side face, the time-mean drag coefficient can be reduced to 60% of its fixed-cylinder value.

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