Hydrokinetic energy on Shreyas Mandre

Oscillating hydrofoil for hydrokinetic power

Thu, 01 Jun 2017 00:00:00 +0000

Between 2013 and 2017 I led an ARPA-E programme at Brown University that took an oscillating hydrofoil for tidal and river power from the equations to 1 kW and 2 kW devices tested in the Taunton River and the Cape Cod Canal — technology readiness level 1 to 6. The physics is the lift a foil keeps after the flow separates from its leading edge, a cousin of the vortex-driven waving of marine grass; the engineering is a machine that turns it into power under both directions of the tide.

Confinement effects on energy harvesting by a heaving and pitching hydrofoil

Tue, 01 Jan 2019 00:00:00 +0000

Wall confinement effects on the energy harvesting performance by a flapping hydrofoil (aspect ratio 4.5) have been investigated in a circulating water flume at a Reynolds number of 50,000. Measurements of hydrodynamic forces are taken for three different confinement configurations (unconfined, one-wall and two-wall confinement) and a series of confinement levels for each configuration. Compared with the unconfined situation, a significant improvement of efficiency performance is obtained for strong two-wall confinement due to the enhancement of the hydrodynamic forces, while only a modest increase is observed in the one-wall confinement configuration.

Energy harvesting performance and flow structure of an oscillating hydrofoil with finite span

Sat, 01 Apr 2017 00:00:00 +0000

The energy harvesting performance and resulting flow structures of a hydrofoil oscillating in pitch and heave are studied experimentally in a water flume. The shape of a hydrofoil cross-section is shown to have negligible influence on the power generation for the geometries tested. It is found that contribution to efficiency from heaving motion increases with reduced frequency at optimal pitching amplitude. However, contribution to efficiency from pitching motion decreases with reduced frequency because the development of a leading-edge vortex during the stroke is delayed at the high reduced frequency.