Preliminary design guidelines for a vortex-based energy harvester for water flows

Abstract

The proposed study presents preliminary design guidelines for vortex-induced vibration energy harvesting devices. In particular, this study combines high-quality computational fluid dynamics techniques to systematically examine the oscillatory behaviour of flow-induced vibration cylinders in cross-flow configurations. Simple cylinders are examined and modelled in terms of masses, damping, and stiffness. The design maps are derived after a comprehensive validation of the numerical model. The maps link the most important flow characteristics at which the device should be installed to the foundational variables relevant to energy recovery and the most important flow properties on which the device must be installed. The results show that the lock-in conditions are achieved with a reduced velocity value of about 5. Additionally, the analysis revealed that the density ratio is a key design parameter, since the functional properties of the device are ensured only for modest values, roughly around 10. In essence, the results provide significant insights into the fluid mechanics of the system, direct indications of the nondimensional groups that regulate system physics, and practical tips for its design.