Bending-Torsional Flutter of a Slender Web in a Cross Flow

<jats:p>This paper presents a flutter analysis of a slender web in a cross air flow. In the flutter analysis, a Doublet-point method (DPM) [1] based on an unsteady lifting surface theory is used to calculate the unsteady fluid force acting on the sheet surface. The equation of motion of the web with tension is derived by using the finite element method (FEM). Flutter velocity, frequency and mode are examined through the root locus of the flutter determinant of the system with changing flow velocity of air. In this study, these flutter characteristics derived by flutter analysis are compared with wind-tunnel experiments. The influence of tension of the web on flutter velocity, frequency and mode is clarified.</jats:p> <jats:p>As tension of the web becomes higher, the flutter velocity and corresponding frequency increase. In any tension, coupled mode flutter of bending and torsional modes occurs. Then, local work done by the fluid force around the upstream end of the web is positive. On the other hand, near the downstream end of the web, the local work is negative.</jats:p>