Based on the discrete vortex method, a conformal mapping technique is used to solve Karman vortex street-airfoil interaction.

The emission frequency of the Karman vortex street occurred in series from the blades and tongue is varing with the running condition.

There are two shedding modes along the slender axes when the angle of attack is very high. The Karman vortex shedding region is located in afterbody while the nose vortices region is near the apex.