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Fig. 1. Sketches of the reference frames and wing motion. OXYZ is an
inertial frame, with the XY plane in the horizontal plane.
o'x'y'z' is
another inertial frame, with the x'y' plane in
stroke plane. oxyz is a frame fixed on the wing, with the x
axis along the wing chord, and the y axis along the wing span.
,
positional angle of the wing;
min and
max,
minimum and maximum positional angle, respectively;
, angle of attack
of the wing; ß, stroke plane angle; V
,
free-stream velocity; and R, wing length. CL and
CT, coefficients of lift and thrust, respectively;
Cl and Cd, coefficients of wing lift
and wing drag, respectively; Cd',
x' component of Cd..