Numerical Investigation of Dynamic Stall Control via Airfoil Thickness Variation

Abstract

Numerical experiments are conducted to investigate the effects of deformation control strategy in a dynamic stall control via active thickness variation. The aim is to clarify the dominant control parameters for an optimal thickness variation strategy. To achieve this goal, the thickness variation strategies are determined by superposing two components, a linear variation and a curved one. The effects of the control parameters on the lift stall angle, the moment stall angle, the maximum lift coefe cient, and the maximum negative pitching moment are thoroughly examined. The results indicate that dynamic stall characteristics have a strong dependency on the thickness variation strategies of each phase. From the detailed analyses, it is found that 1 ) the variation strategies in the upstroke have a signie cant effect on the vortex formation at the leading edge and the vortex shedding speed is dependent of the thickness variation in the downstroke, 2 ) the dominant parameters in this control strategy are the sign and the magnitude of the curved variation, and 3 ) there exists an optimal thickness variation strategy to control of lift characteristics or moment characteristics.