UNSTEADY AIRFOILS.

Abstract

The paper illustrates some basic concepts for an inviscid incompressible fluid by means of thin-airfoil theory. The unsteady flow effects are particularly investigated. Studies of unsteady-airfoil flows have been motivated mostly by efforts to avoid or reduce such undesirable effects as flutter, vibrations, buffeting, gust response, and dynamic stall. This requires predicting the magnitude and phase (or time lag) of the unsteady fluid-dynamic loads on thin lifting surfaces. Some attention has also been given to potentially beneficial effects of unsteadiness.