Aerodynamic characteristics of fundamental cross section

[30] LARGE AMPLITUDE AERODYNAMIC VIBRATION OF RECTANGULAR CYLINDER WITH A SIDE RATIO OF TWO WITH VARIOUS ANGLES OF ATTACK

○Yuta Sasaki¹, Tomomi Yagi¹, Masaaki Hamano², Hisato Matsumiya³, Takashi Nishihara³ (1.Kyoto University Graduate School of Engineering Department of Civil and Earth Resources Engineering, 2.Shutoko Metropolitan Expressway Company Limited , 3.Central Research Institute of Electric Power Industry Civil Engineering Research Laboratory)

Keywords:coupled vibration, galloping, torsional flutter, quasi-steady aerodynamic force

In general, aerodynamic instabilities of bluff bodies are investigated in the very small amplitude region. In this study, a rectangular cylinder with a side ratio of two is used to investigate its large amplitude vibrations under three DOF condition with various angles of attack. Then, the various kinds of self-induced vibration with large amplitudes were observed. To understand these responses, the time history analyses using quasi-steady aerodynamic forces are applied. Then, the large amplitude vibrations can be divided into the two following phenomena. One is coupled 3DOF vibration which can be explained by the quasi-steady aerodynamic forces, and the other is coupled 3DOF vibration which caused by torsional 1DOF instability.