Suppression of vortex-induced vibration of a circular cylinder by a passive-jet flow control

In this study, vortex-induced vibrations (VIVs) of a spring system-supported circular cylinder model are suppressed via passive-jet flow control in wind tunnel experiments. A laser displacement measurement system is employed to obtain the vibration response of the test model with and without a passive-jet control scheme. The results indicate that the VIV oscillation amplitudes and frequency lock-in ranges of the controlled models are smaller than those of the baseline case. In addition to the vibration measurements, the pressure distribution in the test model is measured with a digital pressure measurement system. According to the surface pressure results, the mean pressures of the leeward surface are lifted, and the root-mean-square (RMS) pressures on the cylinder surface are suppressed compared with those of the baseline case. Moreover, in the controlled cases, the mean drag and lift fluctuations are remarkably alleviated, and the Reynolds shear stress in the cylinder wake decreases considerably. All results indicate that the effectiveness of the passive-jet flow control in this investigation is determined by the spacing of two neighboring jet pipes. Moreover, a linear correlation analysis of the surface pressures reveals that the correlation of the external surface pressure is tremendously disturbed by the passive-jet flow control.