Enhancing vortex-induced vibrations of a cylinder with rod attachments for hydrokinetic power generation

摘要

A new converter consisting of a circular cylinder on an end-spring is proposed to harness hydrokinetic power from water flow and tides. Two cylindrical rods with a small diameter are attached to both sides of a cylinder parallel to the axis of symmetry of the cylinder above and below the stagnation point. It is inspired by the trembling of cables with ice attached in barely noticeable winds. Numerical CFD (Computational Fluid Dynamics) simulations are carried out using a two-dimensional Reynolds-Averaged Navier-Stokes equations solver, which is based on ANSYS Fluent using User-defined Function. It is found that two small-diameter cylindrical rods attached to the main cylinder at 55° to 65° with respect to the incoming flow significantly expand the aeroelastic instability range for the main cylinder thereby increasing the generated power. The water flow energy harvester with this structure harvests energy exceeding the onset speed of VIV and is sustained over a wide water speed range.