Flow control on the vortex-induced vibration of a circular cylinder using a traveling wave wall method

In this study, a traveling wave wall flow control method was adopted to suppress the vortex-induced vibration of an elastically mounted circular cylinder with 2 degrees of freedom in the range of a high Reynolds number (Re = 3.0 x 10(4) - 4.3 x 10(4)). First, the vortex-induced vibration characteristics of the circular cylinder (under eight different incoming velocities) were studied based on a two-dimensional computational fluid dynamic numerical simulation and the numerical simulation results were compared and validated with those from wind tunnel tests. Next, the traveling wave wall started from t = 0 to control the vortex-induced vibration of the circular cylinder. This study mainly focused on the control effectiveness of using the traveling wave wall control method to suppress the vortex-induced vibration of a circular cylinder with 2 degrees of freedom. The crossflow and the inline flow displacements, the centroid motion trajectories, the lift and drag forces, and the vorticity contours around the cylinder were thoroughly analyzed for both cases, that is, vortex-induced vibration (uncontrolled) and traveling wave wall (controlled) under eight reduced velocities. The results indicated that the traveling wave wall could effectively eliminate the oscillating wake of a spring-supported cylinder. The stable and symmetric shear layers were distributed in the wake of the controlled cylinder and the alternate shedding vortex street did not form from the beginning to the end. As a result, the lift coefficient fluctuation and drag coefficient mean were greatly decreased; however, the fluctuation of drag coefficient slightly increased. Under all reduced velocities, the crossflow displacement amplitudes of controlled cylinder decreased by 95% in comparison with that of the uncontrolled cylinder. This means that the traveling wave wall flow control method achieved the goal of suppressing the vortex-induced vibration of the circular cylinder.