Experimental study of vortex-induced vibrations of a cylinder near a rigid plane boundary in steady flow

Abstract

In this study, the vortex-induced vibrations of a cylinder near a rigid plane boundary in a steady flow are studied experimentally. The phenomenon of vortex-induced vibrations of the cylinder near the rigid plane boundary is reproduced in the flume. The vortex shedding frequency and mode are also measured by the methods of hot film velocimeter and hydrogen bubbles. A parametric study is carried out to investigate the influences of reduced velocity, gap-to-diameter ratio, stability parameter and mass ratio on the amplitude and frequency responses of the cylinder. Experimental results indicate: (1) the Strouhal number (St) is around 0.2 for the stationary cylinder near a plane boundary in the sub-critical flow regime; (2) with increasing gap-to-diameter ratio (e 0 /D), the amplitude ratio (A/D) gets larger but frequency ratio ( f / f n ) has a slight variation for the case of larger values of e 0 /D(e 0 /D > 0.66 in this study); (3) there is a clear difference of amplitude and frequency responses of the cylinder between the larger gap-to-diameter ratios (e 0 /D > 0.66) and the smaller ones (e 0 /D < 0.3); (4) the vibration of the cylinder is easier to occur and the range of vibration in terms of V r number becomes more extensive with decrease of the stability parameter, but the frequency response is affected slightly by the stability parameter; (5) with decreasing mass

Flow characteristics around a circular cylinder subjected to vortex-induced vibration near a plane boundary

“…The velocities that induce cylinder vibration span from u 0 ¼15.89 to 19.09 cm/s (V r ¼5.64-6.78), which is a rather narrow range. This phenomenon agrees with the observations in the high-m * ζ condition by Yang et al (2009), who found that significant vibrations appear within a narrow range with V r E5.09-6.51 in the intermediate region. Fig.…”

“…Fredsøe et al (1987) observed that the vibrating characteristics of the cylinder is clearly influenced by the boundary when G 0 /Do1.0. Yang et al (2009) investigated the amplitude and frequency responses of a vibrating cylinder under different G 0 /D, and found an obvious difference between larger G 0 /D (G 0 /D 40.66) and smaller ones (G 0 /Do0.3). Wang et al (2013) used PIV to investigate the effect of a plane boundary on vortex formation.…”

“…Fredsøe et al, 1987;Yang et al, 2009) on this problem have focused on the effect of G 0 /D on the vibration amplitude, while the PIV study by Wang et al (2013) deals with the qualitative characterization of the flow pattern. So far, there is no detailed quantitative study on the flow field that is essential for a thorough understanding of the underlying physics.…”

Freely vibrating circular cylinder in the vicinity of a stationary wall

“…Yang et al (2011) compared the dynamic response of cylinder near a deformable wall in both 1-DoF and 2-DoF cases. Yang et al (2009) showed that the dimensionless vibration frequency for smaller e/D of 0.06 and 0.30 are much larger than those for larger e/D of 0.66 and 0.88, respectively, at the same reduced velocity. For smaller mass ratio m n , the vibration range is larger.…”

Experimental study on onset of Vortex-Induced Vibration of a pipeline near a seabed

“…VIV of a pipeline, which has been considered as one of the most important reasons for a pipeline failure, may occur when the ocean flow crossing the pipeline is larger than a certain value. Most existing studies on VIV were mainly focused on the vibration amplitude and frequency for a wall-free (Feng, 1968;Sarpkaya, 2004;Govardhan & Williamson, 2006;Vandiver, 2012) or near-bed cylinder (Jacobsen et al, 1984;Yang et al, 2009;Zang & Gao, 2014). However, the critical condition for the onset of VIV is also a crucial parameter in practical engineering, as it is closely related to the allowable length for avoiding VIV of the spanning pipeline.…”