Perspective: Unsteady Wing Theory—The Kármán/Sears Legacy

Abstract

The aerodynamic analysis of wings and their vortex wakes is discussed from a perspective of its relation to the 1938 work of Kármán and Sears. The key concepts from this early paper on the analysis of airfoils in small amplitude unsteady motion are reviewed. These concepts are then used as a point of departure for developing techniques for calculating and interpreting the aerodynamic characteristics of both airfoils in large amplitude motion with deforming vortex wakes, and maneuvering low-aspect-ratio wings with leading-edge separation. Calculated examples are presented for this extended set of applications, and are compared to related analyses and experiments.