WIND-EXCITED OVALLING VIBRATION OF A THIN CIRCULAR CYLINDRICAL-SHELL

Vibration characteristics and growth mechanisms of wind-excited ovalling vibration of thin circular cylindrical shells which have dimensions like silos were investigated by using model shells made of polyester film in a wind tunnel. In the experiments wind pressure characteristics acting on the shell, static and dynamic responses of the shell and the effect of additional air force induced by the vibration of the shell were measured. The results obtained fom this study suggest that the ovalling vibration of these kinds of shell is excited by an aerodynamic negative damping effect when the turbulence intensity of the approaching flow is small. The relationship between the inertia force of the shell and the mean lateral force acting on the shell at the onset of ovalling vibration is discussed.