A vorticity dynamics view of “effective slip boundary” with application to foil-flow control

Abstract

Effective slip boundary (ESB) formed on textured surfaces provides a very promising method to control complex separated flow. It is becoming technically feasible due to the rapid development of new materials and other innovative technologies. In this paper, we explore the underlying physical mechanisms and guiding principle of this new control strategy by theory of boundary vorticity dynamics. We illustrate the theory by a numerical study of using textured surface to control separated foil-flow. Unlike traditional control strategy working on existing boundary layers, this new strategy aims at weakening or even eliminating the boundary layer itself by manipulating its origin. Significant ESB control effects are observed on suppressing separation, enhancing lift, and reducing drag at stall angle of attack.