© 1982 by Oxford University Press
SOLUTION OF THE UNSTEADY SUBSONIC THIN AIRFOIL PROBLEM
( Department of Aeronautics and Astronautics, Purdue University West Lafayette, Indiana 47907, U.S.A. )
The problem of a thin airfoil subject to simple harmonic disturbances in a uniform subsonic free stream is solved by extension of a technique developed earlier for a stationary strip vibrating in a uniform fluid. Explicit expressions are given for the lift and moment, acoustic directivity pattern, and total acoustic power for arbitrary upwash and, in particular, for the elementary disturbances: plunge, pitch, and a stationary transverse gust. Numerical results for a simple skewed gust are presented and compared to the high-frequency asymptotic theory of Martinez and Widnall.