Parametric study of a two degree-of-freedom cylinder subject to vortex-induced vibrations

2008 ◽  
Vol 24 (8) ◽  
pp. 1284-1293 ◽  
Author(s):  
D. Lucor ◽  
M.S. Triantafyllou
Keyword(s):  
Parametric Study ◽  
Degree Of Freedom ◽  
Vortex Induced Vibrations ◽  
Two Degree Of Freedom

Three-Dimensional Numerical Simulations of Circular Cylinders Undergoing Two Degree-of-Freedom Vortex-Induced Vibrations

2006 ◽  
Vol 129 (3) ◽  
pp. 158-164 ◽  
Author(s):  
Juan P. Pontaza ◽  
Hamn-Ching Chen
Keyword(s):  
Numerical Simulations ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Degree Of Freedom ◽  
Circular Cylinders ◽  
Numerical Implementation ◽  
Vortex Induced Vibrations ◽  
Multiple Processors ◽  
Structural Mass ◽  
Two Degree Of Freedom

In an effort to gain a better understanding of vortex-induced vibrations (VIV), we present three-dimensional numerical simulations of VIV of circular cylinders. We consider operating conditions that correspond to a Reynolds number of 105, low structural mass and damping (m*=1.0, ζ*=0.005), a reduced velocity of U*=6.0, and allow for two degree-of-freedom (X and Y) motion. The numerical implementation makes use of overset (Chimera) grids, in a multiple block environment where the workload associated with the blocks is distributed among multiple processors working in parallel. The three-dimensional grid around the cylinder is allowed to undergo arbitrary motions with respect to fixed background grids, eliminating the need for grid regeneration as the structure moves on the fluid mesh.

On the effect of mechanical non-linearities on vortex-induced lock-in vibrations

2016 ◽  
Vol 22 (10) ◽  
pp. 1922-1935 ◽  
Author(s):  
G Piccardo ◽  
F Tubino ◽  
A Luongo
Keyword(s):  
Duffing Oscillator ◽  
Point Of View ◽  
Degree Of Freedom ◽  
Modal Interaction ◽  
Van Der Pol ◽  
Vortex Induced Vibrations ◽  
Non Linear ◽  
Limit Cycle Amplitude ◽  
Lock In ◽  
Two Degree Of Freedom

Vortex-induced vibrations at lock-in conditions are modeled through generalized van der Pol-Duffing oscillators endowed with frequency-dependent coefficients, taking inspiration from fluid-elastic models. Accordingly, it is found that the limit-cycle amplitude and the non-linear frequency are mutually dependent (feedback effect), differently from the classic oscillator behavior. Consequently, the mechanical non-linearities, which are often believed to be unimportant, do affect the amplitude of motion. Examples concerning an ideal one degree-of-freedom van der Pol-Duffing oscillator and a two degree-of-freedom model, coarsely representative of a tower building, confirm the importance of this approach also from a technical point of view. Thus, non-linear geometric terms and modal interaction (even in non-resonant cases) can lead to non-negligible modifications of purely aeroelastic problems.

Sign in / Sign up

Export Citation Format

Share Document