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

本文研究了如何将边界层控制方法应用于钝体气动响应的抑制。通过在上游转角设置两个旋转圆柱的正方形棱镜的表面压力和气动响应测量的基础实验，获得了抑制钝体气动响应的有用信息：(1)通过控制旋转圆柱的旋转表面速度，可以控制平均压力和脉动压力。(2)旋转表面速度越高，钝体就越具有流线型。换句话说，通过旋转圆柱体加速边界层，钝体可以改进为细长体。(3)本文研究的两个旋转圆柱体的旋转表面速度的最有效组合是一个静止，另一个旋转，其速度大于接近流速的1.4倍。(4)当两个旋转圆柱体的旋转表面速度相同时，旋转表面速度较大的情况有可能导致方形圆柱体的驰振响应对设定的较高风速的气动响应。(5)气动响应完全可以得到对于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，如何将这种方法应用于实际结构，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.