Vortex-induced vibration suppression of a main circular cylinder with two rotating control rods in its near wake: Effect of the rotation direction

2017 ◽  
Vol 74 ◽  
pp. 469-491 ◽  
Author(s):  
Hongjun Zhu ◽  
Yue Gao
Keyword(s):  
Circular Cylinder ◽  
Vibration Suppression ◽  
Wake Effect ◽  
Near Wake ◽  
Vortex Induced Vibration ◽  
Rotation Direction ◽  
Control Rods

scholarly journals Numerical Investigation on Vortex-Induced Vibration Suppression of a Circular Cylinder with Axial-Slats

2019 ◽  
Vol 7 (12) ◽  
pp. 454 ◽  
Author(s):  
Wei Wang ◽  
Zhaoyong Mao ◽  
Wenlong Tian ◽  
Tingying Zhang
Keyword(s):  
Circular Cylinder ◽  
Frequency Ratio ◽  
Vibration Suppression ◽  
Amplitude Ratio ◽  
Number Range ◽  
Vortex Induced Vibration ◽  
Suppression Effect ◽  
Coverage Ratio ◽  
Region I ◽  
Region Ii

The vortex-induced vibration (VIV) suppression of a circular cylinder with the axial-slats is numerically investigated using the computational fluid dynamics (CFD) method for Reynolds number range of 8.0 × 103–5.6 × 104. The two-dimensional unsteady Reynolds averaged Navier–Stokes (RANS) equations and Shear-Stress-Transport (SST) turbulence model are used to calculate the flow around the cylinder in ANSYS Fluent. The Newmark-β method is used to evaluate structural dynamics. The amplitude response, frequency response and vortex pattern are discussed. The suppression effect of the axial-slats is the best when the gap ratio is 0.10 and the coverage ratio is 30%. Based on the VIV response, the whole VIV response region is divided into four regions (Region I, Region II, Region III and Region IV). The frequency ratio of isolated cylinder jumps between region II and region III. However, the frequency ratio jumps between region I and region II for a cylinder with the axial-slats. The axial-slats destroy the original vortex and make the vortex easier to separate. The online amplitude ratio is almost completely suppressed, and the cross-flow amplitude ratio is significantly suppressed.

scholarly journals Vortex-Induced Vibration Suppression of a Circular Cylinder with Vortex Generators

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Shi-bo Tao ◽  
Ai-ping Tang ◽  
Da-bo Xin ◽  
Ke-tong Liu ◽  
Hong-fu Zhang
Keyword(s):  
Circular Cylinder ◽  
Vibration Suppression ◽  
Angular Position ◽  
Vortex Generator ◽  
Vortex Generators ◽  
Spanwise Direction ◽  
Control Effect ◽  
Vortex Induced Vibration ◽  
Suppression Method ◽  
Skew Angles

The vortex-induced vibration is one of the most important factors to make the engineering failure in wind engineering. This paper focuses on the suppression method of vortex-induced vibration that occurs on a circular cylinder fitted with vortex generators, based on the wind tunnel experiment. The effect of the vortex generators is presented with comparisons including the bare cylinder. The experimental results reveal that the vortex generators can efficiently suppress vortex-induced vibration of the circular cylinder. Vortex generator control can make the boundary layer profile fuller and hence more resistant to separation. The selections of skew angles and the angular position have a significant influence on the vortex generator control effect. By correlation analysis, it can be concluded that the vortex generators can inhibit the communication between the two shear layers and produce streamwise vortices to generate a disturbance in the spanwise direction.

Wake of a Vibrating Cylinder at Re = 105

2011 ◽  
Author(s):  
R. D. Blevins ◽  
Jean-Franc¸ois Saint-Marcoux
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Flow Visualization ◽  
Vortex Dynamics ◽  
Velocity Profiles ◽  
Near Wake ◽  
Vortex Induced Vibration ◽  
Cylinder Flow

Measurements have been made of the wake of a circular cylinder at Reynolds number of 105 for a stationary cylinder and a cylinder vibrating +/− 1.25 diameters under natural vortex induced vibration. Wake velocity profiles were taken at 2, 4, 6, 12, 24 and 50 diameters downstream. The stationary cylinder profile reproduces the well known wake deficit law. The vibrating cylinder near wake is wider, deeper and flatter than that of the stationary cylinder. Flow visualization reveals the vortex dynamics in the wake. Correlation is shown with theory.

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