Flow-Induced Vibration of a rotating circular cylinder using position and velocity feedback

A numerical simulation of transverse flow-induced vibrations of a rotating circular cylinder is presented. Rotation rate and direction is imposed to be proportional either to the cylinder's position or cylinder's velocity. A 2D Lattice Boltzmann method is used to solve the flow dynamics and the cylinder is spring-mounted and free to undergo transverse vibrations. In all cases, non-dimensional mass is 12.7, Reynolds number 100, and zero damping is considered, so the analysis is focused on the role of the rotation law and the reduced velocity. Results are presented in terms of steady-state oscillations characterization (say amplitude and frequency), fluid forces on the cylinder, and wake-pattern topology. It is shown how the imposed rotation changes the cylinder's response significantly, fluid forces on it and the flow field in the wake. Depending on the rotation law imposed flow-induced vibrations can be increased or diminished. The former can be of interest for energy harvesting purposes; whereas the later can be useful to avoid unwanted oscillations. When rotatory law is proportional to the cylinder's position, a galloping-type response has been found. In this case, the cylinder's amplitude can be reasonably well predicted with a quasi-steady theoretical model. For rotation proportional to the cylinder's velocity only vortex-induced-type responses have been found.