1207 Aerodynamic characteristics of rotary wings at low Reynolds numbers(2)

Aiming at providing instructive aerodynamic principles for the MAV (Micro Air Vehicle) design of a mini-helicopter, aerodynamic characteristics of rotary wings of insect and bird sizes were studied numerically using a biology-inspire dynamic flight simulator. A geometrical model was built based on a realistic insect body and wings; a rotating angular velocity for the rotary wing is defined to be identical with that of a flapping insect wing; and an angle of attack is taken to be equal to the mean angle of attack of the flapping wing. Computations of hovering aerodynamics of the insect-type, mini-helicopter were conducted with a specific focus on the effects of the size which varied over a wide range of 1〜10000, and the reduced frequency at 0.382, 0.764 and 1.146. Our results indicate that the LEV (leading-edge vortex) is observed at all the Re numbers detached onto the upper surface of the wing and is responsible for the lift generating as seen in a flapping wing of insect flight. Furthermore, the computed CT/CQ is clearly sensitive to the Reynolds number rather than the reduced frequency.