Base Pressure Measurements on a Circular Cylinder in Subsonic Cross Flow

The two-degrees-of-freedom VIV of the circular cylinder with high mass-ratio is numerically simulated with the software ANSYS/CFX. The VIV characteristic is analyzed in the different conditions (Ur=3, 5, 6, 8, 10). When Ur is 5, 6, 8 and 10, the conclusion which is different from the cylinder with low mass-ratio can be obtained. When Ur is 3, the frequency of in-line VIV is twice of that of cross-flow VIV which is equal to the frequency ratio between drag force and lift force, and the in-line amplitude is much smaller than the cross-flow amplitude. The motion trace is the crescent. When Ur is 5 and 6, the frequency ratio between the drag force and lift force is still 2, but the main frequency of in-line VIV is mainly the same as that of cross-flow VIV and the secondary frequency of in-line VIV is equal to the frequency of the drag force. The in-line amplitude is still very small compared with the cross-flow amplitude. When Ur is up to 8 and 10, the frequency of in-line VIV is the same as the main frequency of cross-flow VIV which is close to the inherent frequency of the cylinder and is different from the frequency of drag force or lift force. But the secondary frequency of cross-flow VIV is equal to the frequency of the lift force. The amplitude ratio of the VIV between in-line and cross-flow direction is about 0.5. When Ur is 5, 6, 8 and 10, the motion trace is mainly the oval.

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Measurements of the dynamic lift force acting on a circular cylinder in cross-flow and exposed to acoustic resonance

Journal of Fluids and Structures ◽

10.1016/j.jfluidstructs.2011.04.009 ◽

2011 ◽

Vol 27 (8) ◽

pp. 1149-1164 ◽

Cited By ~ 13

Author(s):

A. Mohany ◽

S. Ziada

Keyword(s):

Circular Cylinder ◽

Lift Force ◽

Cross Flow ◽

Acoustic Resonance

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Feedback control of vortex shedding from a circular cylinder by cross-flow cylinder oscillations

Experiments in Fluids ◽

10.1007/bf00204635 ◽

1996 ◽

Vol 21 (1) ◽

pp. 49-56 ◽

Cited By ~ 35

Author(s):

H. M. Warui ◽

N. Fujisawa

Keyword(s):

Feedback Control ◽

Circular Cylinder ◽

Vortex Shedding ◽

Cross Flow

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LAMINAR FLOW PAST AN OSCILLATING CIRCULAR CYLINDER IN CROSS FLOW

Journal of Marine Science and Technology ◽

10.51400/2709-6998.1881 ◽

2010 ◽

Vol 18 (3) ◽

Author(s):

Pham Anh-Hung ◽

Lee Chang-Yeol ◽

Seo Jang-Hoon ◽

Chun Ho-Hwan ◽

Kim Hee-Jung ◽

...

Keyword(s):

Laminar Flow ◽

Circular Cylinder ◽

Cross Flow ◽

Flow Past

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Experimental Investigation of Vortex-Induced Vibrations of a Flexibly Mounted Circular Cylinder in Combined Current and Wave Flows

10.1115/omae2021-62931 ◽

2021 ◽

Author(s):

Pierre-Adrien Opinel ◽

Narakorn Srinil

Keyword(s):

Experimental Investigation ◽

Circular Cylinder ◽

Cross Flow ◽

Wave Flow ◽

Regular Wave ◽

Regular Waves ◽

Vortex Induced Vibrations ◽

Flow Frequency ◽

The Cross ◽

Wave Flows

Abstract This paper presents the experimental investigation of vortex-induced vibrations (VIV) of a flexibly mounted circular cylinder in combined current and wave flows. The same experimental setup has previously been used in our previous study (OMAE2020-18161) on VIV in regular waves. The system comprises a pendulum-type vertical cylinder mounted on two-dimensional springs with equal stiffness in in-line and cross-flow directions. The mass ratio of the system is close to 3, the aspect ratio of the tested cylinder based on its submerged length is close to 27, and the damping in still water is around 3.4%. Three current velocities are considered in this study, namely 0.21 m/s, 0.29 m/s and 0.37 m/s, in combination with the generated regular waves. The cylinder motion is recorded using targets and two Qualisys cameras, and the water elevation is measured utilizing a wave probe. The covered ranges of Keulegan-Carpenter number KC are [9.6–35.4], [12.8–40.9] and [16.3–47.8], and the corresponding ranges of reduced velocity Vr are [8–16.3], [10.6–18.4] and [14–20.5] for the cases with current velocity of 0.21 m/s, 0.29 m/s and 0.37 m/s, respectively. The cylinder response amplitudes, trajectories and vibration frequencies are extracted from the recorded motion signals. In all cases the cylinder oscillates primarily at the flow frequency in the in-line direction, and the in-line VIV component additionally appears for the intermediate (0.29 m/s) and high (0.37 m/s) current velocities. The cross-flow oscillation frequency is principally at two or three times the flow frequency in the low current case, similar to what is observed in pure regular waves. For higher current velocities, the cross-flow frequency tends to lock-in with the system natural frequency, as in the steady flow case. The inline and cross-flow cylinder response amplitudes of the combined current and regular wave flow cases are eventually compared with the amplitudes from the pure current and pure regular wave flow cases.

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