EXPERIMENTS OF VORTEX-INDUCED VIBRATION FOR A SMOOTH CIRCULAR CYLINDER AT MASS RATIOS 3<M*<4

Studies involving vortex-induced vibrations (VIV) are generally conducted in water when the mass ratio is low and in air when it is high. VIV in water gained much attention in the last decade due to the possibility of harnessing hydrokinetic energy and most of the literature on this subject is limited to mass ratios of m* < 2. However, it is known that increasing mass ratio also increases energy harnessing efficiency. In this study, we consider smooth circular cylinders in VIV covering a mass ratio range of 3 < m* < 4 at TrSL3 flow regime. Although studies focusing on this range are not so many, there are considerable discrepancies in results in terms of the amplitude response of the cylinder. Experiments are conducted to allow cross-flow motions while restricting inline vibrations. Our results are discussed in comparison with other experiments published in the literature. We have not observed a correlation between the mass-damping parameter and the maximum amplitudes as previous studies suggest. This is considered to be due to the unreported features of the experimental setups: Cylinder positioning, test section width, and the type of test basin are considered to be affecting the cylinder’s VIV response. Our experiments show that increasing mass ratio narrows down the range of synchronization while the maximum achieved amplitude sails around A* ≈ 0.9.