Passive Energy Extraction Through Oscillation of a Yawing Flat Plate Operating in a Uniform Current

Abstract

The work studies the behavior of a plate positioned vertically to incoming current allowed only to yaw. The intention is to use this or similar device to extract energy from the current. Soon, it became clear that positioning a forward disturbance in front of the flat plate creates a wake that improves dramatically the energy extraction. This disturbance was made by a pile with a semi circle transversal section (D-section pile). Several tests have been run, all with the same dimensions of the flat plate and the D-section pile, but each with a unique combination of the incoming velocity (U), the yawing axis position (a/c), the external spring coefficient (k), the distance between the D-section pile and the leading edge of the flat plate (d). The experimental tests are done in LOC (Laborato´rio de Ondas e Correntes — Waves and Currents Laboratory) in COPPE/Federal University of Rio de Janeiro. The results demonstrate that one such system, if controlled appropriately, has the ability to extract energy efficiently.