An oscillating cylinder with mechanically coupled rotation for energy harvesting *

Flow-induced vibrations (FIV) of elastically mounted cylinders have been the subject of numerous studies, owing to their industrial relevance, especially in energy harvesting applications. Recent investigations focused on the amplification of the maximum vibration amplitude by combining such dynamics with forced rotation.

In this connection, we present a mechanical model consisting of a two-dimensional elastically mounted circular cylinder, immersed in an incompressible stream. The cylinder can undergo both vertical and rotational displacement. However, the rotation is mechanically connected to the translation through a pure rolling motion over a surface at distance R with respect to the cylinder center. This results in a single degree-of-freedom system governed by a forced second order oscillator equation. The forcing term comes from the numerical solution of the incompressible Navier-Stokes equations in which the interface condition is enforced by a direct forcing immersed boundary method.

We explore several working regimes of such device by spanning the parameter space defined by coupling radius R, solid-to-fluid mass ratio m*, and reduced freestream speed U*.