EXPERIMENTAL INVESTIGATION OF VORTEX-INDUCED VIBRATIONS OF A CIRCULAR CYLINDER

A new device to study flow-induced vibrations (FIV) under adjustable structural damping ratio is presented. In the presented work, an elastically-mounted cylinder is considered for validation in the context of vortex-induced vibrations (VIV). A DC motor is coupled to the oscillating mass and allows to simulate for positive or negative damping through forcing. When the forcing is appropriately settled to simulate a low structural damping ratio, the standard three-branch response for such system is well recovered and compare well with the literature. Inversely, when the forcing is settled to simulate high damping ratio, the two-branch response is also well reproduced. Flow velocity surveys obtained with Particle Image Velocimetry (PIV) are reported and show that the different VIV wake modes described in the literature are also well recovered by this new experimental device.