27th Congress of International Council of the Aeronautical Sciences, 19 - 24 September 2010, Nice, France
Paper ICAS 2010-9.4.4

WAKE INTERFERENCE IN AEROELASTIC WIND POWER GENERATION

M. E. Isenberg, E. Garcia
Cornell University, USA

Keywords: aeroelastic, flutter, piezoelectric, wake interference, power

This paper discusses the effects of wake interference on the power output of a small-scale flapping wind-energy harvester. The device itself is similar to a cantilevered beam, with piezoelectrics connected to the sides of the beam at the fixed end, generating a current when they are flexed. An airfoil is connected to the free end of the beam by a flexible joint, causing the device to ‘flap’ back and forth, similar to a fish tail. Subjected to a wind flow of a critical speed, flutter instabilities cause the airfoil to oscillate with coupled pitching and heaving vibrations. Vibrations grow in amplitude until nonlinearities in the system establish a stable limit cycle. When multiple devices are used together in a formation, the disturbance of the flow by the leading device affects the output of downstream devices depending on position.

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