Flutter instability of rectangle and trapezoid flags in uniform flow

An experiment on the flutter instability of rectangle and trapezoid flags is conducted in a low speed wind tunnel and a physical model is proposed to predict the critical velocity of flutter instability of the flags. The nondimensional second moment of area is used to depict the effect of the flag shape on the flutter. The result shows that the method presented in this paper can be used to predict the lower-critical velocity. The change of the flutter envelope and critical velocity is found to be related to the dominant mode. (C) 2010 American Institute of Physics. [doi:10.1063/1.3525920]