ON NON-LINEAR VORTEX LATTICE METHOD FOR WINGS AT LARGE ANGLE OF ATTACK IN STEADY, UNSTEADY FLOW.

With the development of modern aircraft design, great interest has been shown in the separation of flow of wings at a Large angel of attack. The authors calculate the steady, unsteady nonlinear loads of wings at large angle of attack with one NLVLM (Nonlinear lortex Lattice Method) form, and study its main parameters, such as: the location of separation line at the sharp leading edge (ie. the lattice shape selected at the leading edge), the relaxation factor delta added in wake-forming, the length of the shed vortices which must be considered in calculations, and so on. The wake is determined by the moving vortices shed from a wing after the wing starts impulsively from rest. numerical examples show that the calculated results agree closely with experimental data.