Unsteady two-dimensional theory of a flapping wing.

An analytical evaluation of the hydrodynamic force on a single flapping wing is presented, based on the two-dimensional inviscid theory, with the addition of an attached leading-edge vortex. The explicit expression of the force is given and compared with some of the measurements by Dickinson et al. [Science 284, 1954 (1999)] and Sane and Dickinson [J. Expl. Biol. 204, 2607 (2001)] for a fruit fly model wing.