Experimental investigation of vortex- and wake-induced vibrations of tandem cylinders

This paper presents the experimental investigation of the wake-induced vibration (WIV) and vortex-induced vibration (VIV) acting on two circular cylinders. In particular, a riser installed in an offshore field may experience flow interferences between adjacent risers. Accordingly, the scaled models are arranged in a tandem configuration to observe the flow interference between the cylinders. The upstream cylinder is either fixed or allowed to have one-degree of freedom (1-DOF) motion, whereas the downstream cylinder is allowed to have two degrees of freedom (2-DOF) motion. The experimental test is conducted in a circulating water channel with cylinders that are connected by linear springs in two horizontal directions. A three-dimensional displacement metre and load cell are employed to measure the motion and hydrodynamic force of the cylinder, respectively. From the experiment, we identify that there are relative effects between the VIV and WIV with respect to selected parameters.