Vortex trapping on a surface with an indentation and corrugations

This paper explores the possibility of trapping single and multiple vortices on a surface and on an airfoil. Results from the vortex trajectory show that an indented surface and an airfoil with an indentation can stabilize a trapped vortex. That is, when displaced by a finite distance from the equilibrium position, the vortex always moves around its equilibrium position. A boundary with multiple corrugations can be created and incorporated onto an airfoil to trap multiple vortices. Irregular vortex motion has been found when multiple vortices are presented above the corrugations. A method is proposed, allowing the vortices to spiral towards its equilibrium positions.