Power extraction from wind and water streams using flapping wings is known to be an alternative method to harvest renewable energy. The vortical flow structures around and in the wake of a NACA0012 airfoil oscillating with non-sinusoidal pitching and plunging motions are investigated using Digital Particle Image Velocimetry (DPIV) and compared with Navier-Stokes computations to give insight into the physics that determine the performance of an oscillating-wing power generator. A plunge amplitude of 1.05 chords, reduced frequency 0.8, pitch amplitude 73°, pivot point at quarter-chord and mid-chord, phase angles of 90° and 110°, and stroke reversal times ΔTR of 0.1 (rapid reversal) to 0.5 (sinusoidal) are used. It is shown that the vorticity formations are independent of the Reynolds number for the investigated cases (Re = 1100 - 1960). As the airfoil rotation speed during pitch reversals is increased, vortex shedding occurs earlier with higher strength. As the phase angle by which the pitching motion leads the plunging motions is increased, the shed vortex convection distance is also increased. Peak power coefficient (0.86) and efficiency (33%) are found at ΔTR = 0.3 for mid-chord pivot, with values of power coefficient (0.89) and efficiency (31%) at ΔTR = 0.5 for quarter-chord pivot. The leading edge vortex interaction with the airfoil and the timing of its formation and convection has the primary role in the time averaged power output.
|Title of host publication||52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014|
|Publisher||American Institute of Aeronautics and Astronautics Inc.|
|Publication status||Published - 1 Jan 2014|
|Event||52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014 - National Harbor, MD, United States|
Duration: 13 Jan 2014 → 17 Jan 2014
|Name||52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014|
|Conference||52nd AIAA Aerospace Sciences Meeting - AIAA Science and Technology Forum and Exposition, SciTech 2014|
|City||National Harbor, MD|
|Period||13/01/14 → 17/01/14|
FingerprintDive into the research topics of 'Experimental and computational investigation of the flow through an oscillating-wing power generator'. Together they form a unique fingerprint.
Idil Fenercioglu Aydin
- School of Arch, Tech and Eng - Senior Lecturer
- Advanced Engineering Centre