Effect of Attack Angle Fluctuation Superimposed on the Cross-Flow Oscillation of a Rectangular Cylinder in Uniform Flow

The cross-flow oscillation of a rectangular cylinder supported by a cantilever plate-spring system was investigated using a wind tunnel, in order to reveal the effect of attack angle fluctuation superimposed on cross-flow oscillation. Three kinds of support systems were tested in order to give a different phase-shift between attack angle and cylinder displacement. Three rectangular cylinders with the slenderness of 0.5, 1.0 and 2.0 were used to investigate effect of attack angle both on the Ka´rma´n vortex excitation and the galloping. The effect of attack angle fluctuation on oscillation behavior markedly differed among the three rectangular cylinders of different slenderness. When the slenderness was 0.5, attack angle fluctuation had no influence on the oscillation behavior of the cylinder. When the slenderness was 1.0 and 2.0, the oscillation behavior was quite different compared with pure cross-flow oscillation, depending on the support system and slenderness.