NUMERICAL SIMULATION OF SUPPRESSING VORTEX-INDUCED VIBRATION OF AN ELASTICALLY MOUNTED CYLINDER BY TRAVELLING WAVE WALL

The CFD numerical method was employed to simulate the whole process starting from the flow around a fixed cylinder, then to a oscillating cylinder (vortex-induced vibration, VIV) and finally to the oscillating cylinder (VIV) controlled by using a travelling wave wall method. The study mainly focused on using the travelling wave control method to suppressing the VIV of an elastically mounted cylinder with two degrees of freedom at low Reynolds numbers. The cross flow (CF) and inline flow (IL) displacements, the centroid motion trajectories and the lift and drag forces of the cylinder changing with the frequency ratios were analyzed in detail. The results indicate that a series of small scale vortices will be formed in the troughs of the travelling wave wall located on the rear part of the cylinder, and they can effectively control the flow separation from the cylinder surface and then result in eliminating the oscillating wake and suppressing the VIV of the cylinder. The travelling wave whatever starting from the initial time or a some halfway can dramatically suppress the CF and IL vibrations of the cylinder and can significantly decrease the fluctuations of the lift coefficients and the average values of drag coefficients. However, it will simultaneously dramatically increase the fluctuations of drag coefficients.