Instability of an Elastic Strip Hanging in an Airstream

Abstract

The stability of a long, thin elastic strip hanging vertically in a downward flowing airstream was considered. Experimentally it was observed that the strip remained essentially motionless or at most developed a small amplitude bounded oscillation as the air speed was increased until a critical speed was attained beyond which violent oscillations of the free-ended strip occurred. A linear approximate analysis was performed for this problem which accounted for shape-induced lift and bending stiffness of the strip and which closely predicted critical air speeds for this instability. The critical air speed was studied as a function of the length, width, and thickness of the rectangular strip.