Abstract: The aeroelastic behaviour of wings with different types of separated vortex at high incidences is investigated.The unsteady aerodynamic equations and the equations of motion are solved simultaneously in the time domain.The separated vortices shed-ding from the leading-edge and/or side-edge of wings are taken into account by an improved Nonlinear Vortex-Lattice Method.The equations of motion are integrated by Runge-Kutta Method.Wings with different planforms at different basic incidences are consid-ered.It is found that (1) the separated vortex shedding from the leading-or side-edges results in the critical flutter speed of the wing lower,and the higher the basic incidence,the lower the critical flutter speed.(2) the smaller the sweep of wing,the smaller the in-fluence of separated vortex on the aeroelastic characteristics.(3) at certain flight speeds and basic incidences,stable limit cycles ap-pear,and the amplitudes of limit cycles even keep constant when the initial distu rbances of response vary.

Key words: nonlinear vibration, separated flows, numerical method, aeroelastics