Experimental investigation on suppressing circular cylinder VIV by a flow control method based on passive vortex generators

Vortex-induced vibration (VIV) is a typical flow-induced vibration phenomenon, which is usually observed in circular cylindrical structures. This study introduces a flow control method based on passive vortex generators (PVGs) for suppressing the VIV of circular cylindrical structures. A series of wind tunnel experiments were performed using rigid circular cylinder models. Vibration tests were implemented using a spring-mass system for verifying the effectiveness of PVGs, and pressure tests were implemented by using a fixed cylinder model for revealing the aerodynamic mechanisms of PVGs qualitatively. Five geometric parameters of PVGs were tested and the optimal parameters were determined during the wind tunnel experiments. The experiment results prove that the maximum root-mean-square values of the vibration amplitudes can be suppressed by more than 80% by attaching PVGs with optimal parameters on the cylinder surface. According to the pressure test results, PVGs designed suitably can suppress vortex shedding in the cylinder wake flow and weaken the spanwise correlation of the cylinder wake flow. Weakening the wake flow spanwise correlation contributes more to controlling the amplitudes of cylinder VIV. In addition to the control effects on the cylinder VIV, some other aerodynamic phenomena of the cylinder with PVGs were observed and analysed.