Numerical study of vortex-induced vibration of pivoted cylinders

Abstract This study was motivated by an idea of harvesting abundant renewable energy in the ocean currents. In order to capture the energy in the ocean currents, vortex-induced vibration (VIV) is exploited and a new configuration of a cylinder is considered. In particular, we investigate numerically the effect of the cross-sectional shape of a cylinder on VIV, when the cylinder is pivoted at a point in the wake. Three different cross-sectional shapes are tested in this study; their ratios of the minor axis to the major axis are 0.6, 0.8 and 1. We compare numerically hydrodynamic drag and lift forces on the stationary elliptic cylinders. The VIV simulations of these three cylinders show that two ellipses with smaller ratios have two times larger displacements than the circular cylinder with ratio 1. Such a superior performance of the elliptic cylinders is observed over a wide range of reduced velocities. A simplified model of a pivoted cylinder is analyzed to confirm that drag forces contribute positively to excitation torques and consequently VIVs. In order to take advantage of the drag forces which work favorably on VIVs, the pivot should be placed in the wake.

[1]  M. Braza,et al.  Physical analysis of the transition to turbulence in the wake of a circular cylinder by three-dimensional Navier–Stokes simulation , 1998, Journal of Fluid Mechanics.

[2]  Kamaldev Raghavan,et al.  Reduction/Suppression of VIV of Circular Cylinders Through Roughness Distribution at 8×103 < Re < 1.5×105 , 2008 .

[3]  F. Varas,et al.  Heat transfer enhancement in micro-channels caused by vortex promoters , 2010 .

[4]  Charles H. K. Williamson,et al.  Defining the ‘modified Griffin plot’ in vortex-induced vibration: revealing the effect of Reynolds number using controlled damping , 2006, Journal of Fluid Mechanics.

[5]  J. T. Klamo,et al.  On the maximum amplitude for a freely vibrating cylinder in cross-flow , 2005 .

[6]  G. Karniadakis,et al.  Spectral/hp Element Methods for CFD , 1999 .

[7]  Emmanuel de Langre,et al.  Energy harvesting using vortex-induced vibrations of tensioned cables , 2012 .

[8]  Atsuo Sueoka,et al.  Quenching of vortex-induced vibrations of towering structure and generation of electricity using Hula-Hoops , 2004 .

[9]  Stergios Liapis,et al.  Reynolds Number Effects on the Vortex-Induced Vibration of Flexible Marine Risers , 2012 .

[10]  Spencer J. Sherwin,et al.  Comparison of wall boundary conditions for numerical viscous free surface flow simulation , 2004 .

[11]  Anthony T. Patera,et al.  A Legendre spectral element method for simulation of unsteady incompressible viscous free-surface flows , 1990 .

[12]  J. Meseguer,et al.  Determination of Maximum Mechanical Energy Efficiency in Energy Galloping Systems , 2015 .

[13]  G. Karniadakis,et al.  Suppressing vortex-induced vibrations via passive means , 2009 .

[14]  Z. J. Ding,et al.  Lift and Damping Characteristics of Bare and Straked Cylinders at Riser Scale Reynolds Numbers , 2004 .

[15]  G. Triantafyllou,et al.  Elimination of vortex streets in bluff-body flows. , 2008, Physical review letters.

[16]  George Em Karniadakis,et al.  Dynamics and flow structures in the turbulent wake of rigid and flexible cylinders subject to vortex-induced vibrations , 1999, Journal of Fluid Mechanics.

[17]  Kamaldev Raghavan,et al.  VIVACE (Vortex Induced Vibration Aquatic Clean Energy): A New Concept in Generation of Clean and Renewable Energy From Fluid Flow , 2006 .

[18]  G. Karniadakis,et al.  A direct numerical simulation study of flow past a freely vibrating cable , 1997, Journal of Fluid Mechanics.

[19]  Computation of free surface flows with a projection FEM in a moving mesh framework , 2003 .

[20]  George E. Karniadakis,et al.  A convergence study of a new partitioned fluid-structure interaction algorithm based on fictitious mass and damping , 2012, J. Comput. Phys..