Mangrove-Like System for Harvesting Tidal Energy

A mangrove-like system to harvest hydrokinetic energy from tidal stream was designed and tested for different flow conditions. The energy harvesting system was composed of an array of cylinders hinged at a pivot point above the water’s surface allowing one degree of freedom. An electric generator composed of a pair of magnets attached of the cylinders and a winding was used to transfer the mechanical motion to electrical energy. The model was tested in a water for different patch configurations, hinged stiffness’s and flow velocities ranging from 2 to 15 cm/s. The patch kinematics and voltage with no load were measured. In addition, the wake downstream the patch was measured with particle image velocimetry. It was found that the patch started to oscillate after reaching some critical velocity. As the spacing between the cylinders increased the critical velocity to start the oscillation decreased. We present the hydrodynamics and performance of the energy harvesting system for the different conditions considered. Our results suggest that the cylinder arrangement and hinged stiffness can be tuned arrays to maximize the energy harvested at different flow conditions.