Experimental investigation of a flow-induced oscillating cylinder with two degrees-of-freedom

The phenomenon of flow-induced vibration of bluff bodies has been studied extensively. The vast majority of these studies have concentrated solely on one degree-of-freedom oscillation in the inline or cross-flow directions. Herein, experiments were carried out with a cylinder in a water channel with two degrees-of-freedom. The cylinder was cantilever mounted with a low natural frequency (typically 65 Hz) in the inline and cross-flow directions. The Reynolds number fell in the range 1.17 × 103 < Re < 2.6 × 104. The oscillating frequency of the cylinder and the surrounding flow were measured simultaneously using high temporal resolution particle image velocimetry (PIV), which is non-intrusive with respect to the flow and has high spatial and temporal resolutions. The vibration of the cylinder was found to be anisotropic. There was a discrepancy between the vibration frequencies in the inline and cross-flow directions, the difference being a function of reduced velocity.