Flow-induced oscillations of tandem tethered cylinders in a channel flow

In single degree-of-freedom (DOF) flow-induced oscillation studies of tandem rigid cylinders, the system most often consists of a front fixed cylinder and a trailing cylinder that is constrained to move perpendicular to the flow. We have conducted experiments in a water channel to investigate the behavior of a single DOF system of cylinders in which the trailing cylinder is constrained to move in a circular arc about the leading cylinder. We will discuss the dynamic response of the trailing cylinder for Reynolds numbers ranging from 10,000 to 20,000 and for inter-cylinder spacings from 3D to 5D, where D is the diameter of the cylinders. The experiments show a multi-frequency response that cannot be classified as a simple harmonic oscillator, as is assumed in typical tandem cylinder models. We compare our results with existing work on transversely constrained cylinders to determine the effect of tethering the cylinders.