Two-dimensional vortex shedding of a circular cylinder

2001 ◽  
Vol 13 (3) ◽  
pp. 557-560 ◽  
Author(s):  
C.-Y. Wen ◽  
C.-Y. Lin
Keyword(s):  
Circular Cylinder ◽  
Vortex Shedding ◽  
Two Dimensional

The vortex-shedding process behind two-dimensional bluff bodies

1982 ◽  
Vol 116 ◽  
pp. 77-90 ◽  
Author(s):  
A. E. Perry ◽  
M. S. Chong ◽  
T. T. Lim
Keyword(s):  
Circular Cylinder ◽  
Flow Visualization ◽  
Vortex Shedding ◽  
Bluff Bodies ◽  
Two Dimensional ◽  
Closed Cavity ◽  
Time Exposure ◽  
Starting Flow ◽  
Visualization Techniques ◽  
Insight Into

Using a variety of flow-visualization techniques, the flow behind a circular cylinder has been studied. The results obtained have provided a new insight into the vortex-shedding process. Using time-exposure photography of the motion of aluminium particles, a sequence of instantaneous streamline patterns of the flow behind a cylinder has been obtained. These streamline patterns show that during the starting flow the cavity behind the cylinder is closed. However, once the vortex-shedding process begins, this so-called ‘closed’ cavity becomes open, and instantaneous ‘alleyways’ of fluid are formed which penetrate the cavity. In addition, dye experiments also show how layers of dye and hence vorticity are convected into the cavity behind the cylinder, and how they are eventually squeezed out.

Inviscid Model of Two-Dimensional Vortex Shedding by a Circular Cylinder

AIAA Journal ◽  
1979 ◽  
Vol 17 (11) ◽  
pp. 1193-1200 ◽  
Author(s):  
Turgut Sarpkaya ◽  
Ray L. Schoaff
Keyword(s):  
Circular Cylinder ◽  
Vortex Shedding ◽  
Two Dimensional

Numerical Simulation of Flow over a Circular Cylinder at Low Reynolds Number

2011 ◽  
Vol 255-260 ◽  
pp. 942-946
Author(s):  
Hua Bai ◽  
Jia Wu Li
Keyword(s):  
Numerical Simulation ◽  
Circular Cylinder ◽  
Vortex Shedding ◽  
Medial Axis ◽  
Lift Coefficient ◽  
Cross Flow ◽  
Reynolds Numbers ◽  
Control Measures ◽  
Hydrodynamic Characteristics ◽  
Two Dimensional

The hydrodynamic characteristics of a circular cylinder in two-dimensional unsteady uniform cross flow was simulated numerically by the laminar model with the reasonable mesh used the method of fluent. The focus of this numerical simulation was to research the characteristics of pressure distribution, drag coefficient and lift coefficient, and the Strouhal number was calculated at Reynolds-numbers value of 200. The results agree well with experimental data and other numerical results according to the reference. In order to study the control measures of the flow over a circular cylinder, the different baffles inserted at various locations downstream of the cylinder have been compared. The results shows that the vortex shedding of flow over a circular cylinder could be well controlled by place the baffle at a right position of the downstream medial axis of the cylinder, which could reduce drag and resist vibration.

Numerical analysis of two-dimensional motion of a freely falling circular cylinder in an infinite fluid

2008 ◽  
Vol 604 ◽  
pp. 33-53 ◽  
Author(s):  
KAK NAMKOONG ◽  
JUNG YUL YOO ◽  
HYOUNG G. CHOI
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Strouhal Number ◽  
Vortex Shedding ◽  
Velocity Vector ◽  
Density Ratio ◽  
Transverse Motion ◽  
Stream Velocity ◽  
Gravitational Acceleration ◽  
Two Dimensional

The two-dimensional motion of a circular cylinder freely falling or rising in an infinite fluid is investigated numerically for the range of Reynolds number Re, < 188 (Galileo number G < 163), where the wake behind the cylinder remains two-dimensional, using a combined formulation of the governing equations for the fluid and the dynamic equations for the cylinder. The effect of vortex shedding on the motion of the freely falling or rising cylinder is clearly shown. As the streamwise velocity of the cylinder increases due to gravity, the periodic vortex shedding induces a periodic motion of the cylinder, which is manifested by the generation of the angular velocity vector of the cylinder parallel to the cross-product of the gravitational acceleration vector and the transverse velocity vector of the cylinder. Correlations of the Strouhal–Reynolds-number and Strouhal–Galileo-number relationship are deduced from the results. The Strouhal number is found to be smaller than that for the corresponding fixed circular cylinder when the two Reynolds numbers based on the streamwise terminal velocity of the freely falling or rising circular cylinder and the free-stream velocity of the fixed one are the same. From numerical experiments, it is shown that the transverse motion of the cylinder plays a crucial role in reducing the Strouhal number. The effect of the transverse motion is similar to that of suction flow on the low-pressure side, where a vortex is generated and then separates, so that the pressure on this side recovers with the vortex separation retarded. The effects of the transverse motion on the lift, drag and moment coefficients are also discussed. Finally, the effect of the solid/fluid density ratio on Strouhal–Reynolds-number relationship is investigated and a plausible correlation is proposed.

Flow Structure in the Wake of an Oscillating Cylinder

1989 ◽  
Vol 111 (2) ◽  
pp. 139-148 ◽  
Author(s):  
Y. Lecointe ◽  
J. Piquet
Keyword(s):  
Circular Cylinder ◽  
Numerical Solution ◽  
Flow Structure ◽  
Vortex Shedding ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Oscillating Cylinder ◽  
Navier Stokes Equations ◽  
Uniform Stream

The numerical solution of the unsteady two-dimensional Navier-Stokes equations is used to investigate the vortex-shedding characteristics behind a circular cylinder immersed in a uniform stream and performing superimposed in-line or transversed oscillations of a given reduced amplitude.

Sound generation by a two-dimensional circular cylinder in a uniform flow

2002 ◽  
Vol 471 ◽  
pp. 285-314 ◽  
Author(s):  
OSAMU INOUE ◽  
NOZOMU HATAKEYAMA
Keyword(s):  
Circular Cylinder ◽  
Vortex Shedding ◽  
Doppler Effect ◽  
Sound Pressure ◽  
Pressure Pulse ◽  
Positive Pressure ◽  
Pressure Waves ◽  
Two Dimensional ◽  
The Doppler Effect ◽  
Mach Numbers

The sound generated by a circular cylinder in a flow at low Mach numbers is investigated by direct solution of the two-dimensional unsteady compressible Navier–Stokes equations. Results show that sound pressure waves are generated primarily by vortex shedding from the cylinder surface into its wake. When a vortex is shed from one side of the cylinder, a negative pressure pulse is generated from that side whereas a positive pressure pulse is generated from the other side; alternate vortex shedding from the upper and lower sides of the cylinder produces negative and positive pulses alternately and thus produces sound pressure waves on both sides. The dipolar nature of the generated sound is confirmed; lift dipole dominates the sound field. The Doppler effect is shown to play an important role at finite Mach numbers. The direct solutions are also compared with the solutions obtained by Curle's acoustic analogy. The results show that Curle's solution describes well not only the generation mechanism of the sound but also the propagation process if we take the Doppler effect into consideration.

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