Besch and Liu 



P oscillatory lift per unit span of strut along elastic axis, 



positive in direction of positive h 



p spanwise modification factor for noncirculatory loading 



r nondimensional radius of gyration 



s complex eigenvalue 



t time 



V flow speed 



w downwash ; vertical component of flow velocity on foil, 



positive in direction of negative h 



x a nondimensional distance from elastic axis to center of 



gravity, measured perpendicular to elastic axis, posi- 

 tive aft as fraction of semichord b 



y spanwise coordinate along elastic axis of strut 



f damping ratio, giving damping as a fraction of critical 



damping 



amplitude of torsional displacement G 



6 torsional displacement of strut about elastic axis, posi- 



tive when leading edge moves in direction of positive h 



k sweep parameter ; (2b tan A ) / L, 



ea 



ea 



elastic -axis sweep angle, positive for sweepback 



fi approximation to generalized mass ratio for bending 



motion 



M .: . generalized mass ratio 



generalized 



u . approximation to generalized mass ratio for torsional 



^torsion rtr . 6 



motion 



p fluid density 



<r local bending slope of elastic axis dh/dy 



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