Suppression Method of Flexible Structure Aerodynamic Vibration by Active Control of Accelerating Fluid in Separating Shear Flow.

本文研究了如何应用边界层控制方法抑制钝体的气动响应。通过测量上角设置两个旋转圆柱体的方棱镜的表面压力和气动响应的基础实验，得到了抑制钝体气动响应的有用信息。(1)通过控制旋转气缸的回转面速度来控制平均压力和波动压力。(2)较高的回转面速度使钝体具有更强的流线型。换句话说，通过旋转圆柱加速边界层，可以将钝体改进为细长体。(3)本研究中两个旋转气缸的旋转表面速度最有效的组合是一个气缸处于静止状态，另一个气缸以高于接近流速1.4倍的速度旋转。(4)两个旋转圆柱体的旋转面速度相同的情况下，旋转面速度越高，方形圆柱体的飞奔响应的气动响应倾向于越高的开启风速。(5)由于上下侧面压力交替波动的消失，一个旋转气缸可以完全抑制气动响应。如何将这种方法应用到日本政府和一些日本公司提出的超长悬索桥和超高层建筑的实际结构中，将进行广泛的研究。

The present research has been conducted to find the method how to apply the boundary layer control method on the suppression of aerodynamic responses of bluff bodies. The useful informations for suppression of aerodynamic responses of bluff body were obtained from the fundamental experiments of measuring surface pressure and aerodynamic responses of square prism with two rotating cylinders set on upstream corners.(1) The mean and fluctuating pressures can be controlled by controlling the rotary surface velocity of the rotating cylinder.(2) The higher rotary surface velocity leads the bluff body to be a more stream-lined body. In other words, the bluff body can be improved to the elongated body by accelerating the boundary layer by the rotating cylinder.(3) The most effective combination of rotary surface velocities of two rotating cylinders in the present research is the case that one is at rest and another is rotating with the velocity higher than 1.4 times of approaching flow velocity.(4) The case that the both rotating cylinders have the same rotary surface velocity has the tendency that the higher rotary surface velocity leads the aerodynamic responses to the higher on-set wind velocity of the galloping responses of the square cylinder.(5) The aerodynamic responses can be completely suppressed by the one rotary cylinder owing to disappearance of alternative surface pressure fluctuations between upper and lower side surface pressure.The extensive research will be conducted how to apply this method to the practical structures of super-long suspension bridges and super-high buildings which are proposed by Japanese government and some Japanese companies.