An insight into the dynamic stall lift characteristics

摘要

The article presents an insight into the dynamic stall lift characteristics through experimental work and a detailed survey of the seminal articles related to the phenomenon. Of particular interest is the dynamic stall observed on lifting surfaces as they undergo high-rate pitching motions at constant speeds up to a predetermined maximum angle of attack. The effects of several contributing parameters, such as the reduced frequency, Mach and Reynolds numbers of operation and the airfoil geometry, have been investigated. In addition, the behavior of the lift curve slope for an airfoil undergoing constant pitch dynamic stall has been analyzed in detail to gain a better understanding of the mechanism for the unsteady case. The unsteady lift-curve has been broken down into stages and each stage has been analyzed separately. The aim is to obtain a deeper insight into the lift generation mechanism involved in unsteady motion of the airfoil in order to improve the design of flow control techniques to exploit the dynamic stall process for a large range of applications.