Active control for enhancing vortex induced vibration of a circular cylinder based on deep reinforcement learning

2021 ◽  
Vol 33 (10) ◽  
pp. 103604
Author(s):  
Yu-Fei Mei ◽  
Chun Zheng ◽  
Nadine Aubry ◽  
Meng-Ge Li ◽  
Wei-Tao Wu ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Circular Cylinder ◽  
Active Control ◽  
Vortex Induced Vibration

From active learning to deep reinforcement learning: Intelligent active flow control in suppressing vortex-induced vibration

2021 ◽  
Vol 33 (6) ◽  
pp. 063607
Author(s):  
Changdong Zheng ◽  
Tingwei Ji ◽  
Fangfang Xie ◽  
Xinshuai Zhang ◽  
Hongyu Zheng ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Active Learning ◽  
Flow Control ◽  
Active Flow Control ◽  
Vortex Induced Vibration ◽  
Active Flow

Effect of an internal nonlinear rotational dissipative element on vortex shedding and vortex-induced vibration of a sprung circular cylinder

2017 ◽  
Vol 828 ◽  
pp. 196-235 ◽  
Author(s):  
Ravi Kumar R. Tumkur ◽  
Arne J. Pearlstein ◽  
Arif Masud ◽  
Oleg V. Gendelman ◽  
Antoine B. Blanchard ◽  
...  
Keyword(s):  
Circular Cylinder ◽  
Nonlinear Energy Sink ◽  
Stream Velocity ◽  
Rectilinear Motion ◽  
Mean Flow ◽  
Number Range ◽  
Vortex Induced Vibration ◽  
Concomitant Reduction ◽  
Fixed Radius ◽  
Lift And Drag

We computationally investigate coupling of a nonlinear rotational dissipative element to a sprung circular cylinder allowed to undergo transverse vortex-induced vibration (VIV) in an incompressible flow. The dissipative element is a ‘nonlinear energy sink’ (NES), consisting of a mass rotating at fixed radius about the cylinder axis and a linear viscous damper that dissipates energy from the motion of the rotating mass. We consider the Reynolds number range $20\leqslant Re\leqslant 120$, with $Re$ based on cylinder diameter and free-stream velocity, and the cylinder restricted to rectilinear motion transverse to the mean flow. Interaction of this NES with the flow is mediated by the cylinder, whose rectilinear motion is mechanically linked to rotational motion of the NES mass through nonlinear inertial coupling. The rotational NES provides significant ‘passive’ suppression of VIV. Beyond suppression however, the rotational NES gives rise to a range of qualitatively new behaviours not found in transverse VIV of a sprung cylinder without an NES, or one with a ‘rectilinear NES’, considered previously. Specifically, the NES can either stabilize or destabilize the steady, symmetric, motionless-cylinder solution and can induce conditions under which suppression of VIV (and concomitant reduction in lift and drag) is accompanied by a greatly elongated region of attached vorticity in the wake, as well as conditions in which the cylinder motion and flow are temporally chaotic at relatively low $Re$.

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