MODELING THE UNSTEADY LIFT AND DRAG ON A FINITE-LENGTH CIRCULAR CYLINDER IN CROSS-FLOW

2000 ◽  
Vol 14 (6) ◽  
pp. 799-817 ◽  
Author(s):  
D.E. CAPONE ◽  
G.C. LAUCHLE
Keyword(s):  
Circular Cylinder ◽  
Finite Length ◽  
Cross Flow ◽  
Lift And Drag ◽  
Unsteady Lift

Numerical Simulation of Vortex Shedding Past a Circular Cylinder in a Cross-Flow at Low Reynolds Number With Finite Volume-Technique: Part 1 — Forced Oscillations

2007 ◽  
Author(s):  
Antoine Placzek ◽  
Jean-Franc¸ois Sigrist ◽  
Aziz Hamdouni
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Circular Cylinder ◽  
Finite Volume ◽  
Vortex Shedding ◽  
Stokes Equations ◽  
Cross Flow ◽  
Forced Oscillations ◽  
Lift And Drag ◽  
Wake Characteristics

The numerical simulation of the flow past a circular cylinder forced to oscillate transversely to the incident stream is presented here for a fixed Reynolds number equal to 100. The 2D Navier-Stokes equations are solved with a classical Finite Volume Method with an industrial CFD code which has been coupled with a user subroutine to obtain an explicit staggered procedure providing the cylinder displacement. A preliminary work is conducted in order to check the computation of the wake characteristics for Reynolds numbers smaller than 150. The Strouhal frequency fS, the lift and drag coefficients CL and CD are thus controlled among other parameters. The simulations are then performed with forced oscillations f0 for different frequency rations F = f0/fS in [0.50–1.50] and an amplitude A varying between 0.25 and 1.25. The wake characteristics are analysed using the time series of the fluctuating aerodynamic coefficients and their FFT. The frequency content is then linked to the shape of the phase portrait and to the vortex shedding mode. By choosing interesting couples (A,F), different vortex shedding modes have been observed, which are similar to those of the Williamson-Roshko map.

scholarly journals Dynamics of the Tip Vortices in the Wake Behind a Circular Cylinder of Finite Length

2020 ◽  
Vol 328 ◽  
pp. 05008
Author(s):  
Václav Uruba ◽  
Pavel Procházka
Keyword(s):  
Circular Cylinder ◽  
Finite Length ◽  
Ground Plane ◽  
Cross Flow ◽  
Cylinder Axis ◽  
Thin Boundary Layer ◽  
Time Resolved ◽  
Vortical Structures ◽  
Tip Vortices ◽  
Piv Technique

The dynamics of the tip vortices in the wake behind a wall-mounted finite-length circular cylinder of the aspect ratio 2 was studied experimentally using time resolved stereo PIV technique. The cylinder was mounted normal to a ground plane and it was subjected to a cross-flow with thin boundary layer developed on the wall, the Reynolds number based on inflow velocity and cylinder diameter was 9.7 thousands. The dynamics of tip vortices were analysed using the POD method applied to the plane perpendicular to the flow close to the cylinder. Besides the decaying power spectrum, slower that the Kolmogorov-type one, the two distinct frequencies were detected on Strouhal numbers 0.09 and 0.15. These frequencies could be linked to the vortical structures dynamics in the wake. The frequency Sh = 0.15 corresponds to predominantly spanwise vortices dynamics with anti-symmetrical patterns with respect to the cylinder axis, while the frequency Sh = 0.09 corresponds to mainly streamwise vortical structures dynamics with symmetrical patterns respectively. Thus, the von Kármán vortex street was detected on Strouhal frequency 0.15.

Numerical Simulation on Vortex-Induced Vibration of an Elastically Mounted Circular Cylinder With Two Degrees-of-Freedom

2011 ◽  
Author(s):  
Zhiyong Huang ◽  
Carl M. Larsen
Keyword(s):  
Numerical Simulation ◽  
Circular Cylinder ◽  
Degrees Of Freedom ◽  
Cross Flow ◽  
Flexible Beam ◽  
Vortex Induced Vibration ◽  
Two Degrees Of Freedom ◽  
Drag Forces ◽  
Strip Theory ◽  
Lift And Drag

A two-dimensional numerical simulation is applied to study the forces and responses associated with vortex-induced vibration of an elastically mounted circular cylinder with two degrees-of-freedom, i.e. the cylinder vibrates in in-line and cross-flow directions. This work could be regarded as a first step to carry out the prediction of vortex-induced-vibration responses of a long flexible beam with a number of two-dimension sections along the spanwise based on strip theory. A direct comparison has been made between the numerical results and measured data from the experiment by Jauvtis and Williamson in 2004. The peak cross flow response reaches 1.28 diameters in the present simulations. The profiles between the displacement and transverse force are found to have a good match with the experimental results, and a typical figure of ‘8’ trace is observed between the lift and drag forces in the initial and super-upper branches. Two typical in-line wake structures SS mode and AS mode are well reproduced in the low reduced velocity range. The newly discovered wake pattern 2T mode corresponds to the super-upper branch is also recaptured. Comparison shows that most features of the experiment can be reproduced by the present numerical model, and this model can be regarded a robust tool to investigate the responses, forces and the basic mechanics of vortex induced vibrations of an elastically mounted cylinder with two degrees-of-freedom.

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

scholarly journals Aerodynamics of a Circular Cylinder of Finite Length

1988 ◽  
Vol 1988 (36) ◽  
pp. 27-43
Author(s):  
Yasushi UEMATSU ◽  
Motohiko YAMADA ◽  
Kaoru ISHII
Keyword(s):  
Circular Cylinder ◽  
Finite Length
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