Study of Vortex Induced Vibration of a Flexible Cylinder with Rigid Splitter Plate

Abstract

Flow induced vibration in large chimney or marine riser is always been a matter of concern and continuous efforts are being made to control it. In the present work, a problem of vibration control of a cylindrical body placed in flow is attempted. A two-dimensional numerical study of vortex induced vibration of a flexible cylinder with a rigid splitter plate is carried out at low Reynolds number flow condition. A parametric study to know the effect of length of splitter plate on the level of vortex induced vibration is also done. Four cases of different splitter plate’s length are considered (0.25D, 0.5D, 0.75D and 1D) and vibration response of the cylinder is monitored. In addition, some pre simulations to identify lock-in vibration of the system are also conduced. The results obtained indicate that by adding a splitter plate, vibration level reduces drastically. For a splitter plate of length 0.25D, the vortex induced vibration amplitude reduces up-to 87.50% compared to the case of vibration of cylinder without the splitter plate. The maximum reduction in vibration amplitude is achieved for the length of 0.75D which is 97.50%. Based on the implications in the implementation of such plate on the real structures, a plate of smaller length is finally suggested to use to reduce vibration of circular section structures. It is also found that beyond the length of 0.75D, vibration level increases that may be due to occurrence of galloping instability.