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http://dx.doi.org/10.5139/JKSAS.2016.44.10.843

Aerodynamic Features of Maple Seeds in the Autorotative Flight  

Sohn, Myong Hwan (Department of Aeronautical and Mechanical Engineering, Cheongju University)
Publication Information
Journal of the Korean Society for Aeronautical & Space Sciences / v.44, no.10, 2016 , pp. 843-852 More about this Journal
Abstract
The autorotative flight of maple seeds(Acer palmatum) is numerically simulated based on the 3D geometry and the motion parameters of real seeds. The nominal values of the motion parameters are 1.26 m/s for descent velocity, 133.6 rad/s (1,276 rpm) for spinning rate, $19.4^{\circ}$ for coning angle, and $-1.5^{\circ}$ for pitch angle. A compact leading-edge vortex (LEV) positioned at the inner span of the seed blade causes a large suction pressure on its leeward surface. The suction pressure peaks occur near the leading region of inner span sections. The flow pattern characterized by the prominent LEV and the values of aerodynamic force coefficients obtained in the present study are in good agreement with experimental data measured for a dynamically-scaled robot maple seeds. A spiraling vortex developed in the leeward region advances toward the seed tip and merges with the tip-passing flow, which is considered to be a mechanism of maintaining stable and attached LEV for the autorotating maple seeds.
Keywords
Wind dispersal; Maple seed; Autorotative flight; Numerical simulation; Seed geometry; Leading-edge vortex; Vorticity; Suction pressure distribution;
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