DEVELOPMENT OF THE SYSTEM FOR MEASURING THREE DIMENSIONAL UNSTABLE FLOW IN MAGNETIC STORAGE DISKS

圆盘间的非稳定流动是近年来研究的一个重要课题，它涉及到圆盘的颤振、碰撞、热问题和尘埃的行为。由于非定常流场的复杂性和三维结构，目前有关非定常流场的研究报道较少，本文利用氢气泡法和图像增强技术，研制了一套非定常流场三维速度场和频率的测量系统。我们按照以下程序执行项目：（1）实验装置的设计和制造，（2）驱动盘的控制系统的设计和制造，（3）产生氢气泡的电路的设计和制造，（4）实验，（5）图像分析方法的开发，（6）图像分析软件的开发，（7）建立了系统的验证方法。 ...更多信息 模拟护罩的丙烯酸圆柱体和两个平行旋转的玻璃盘的边缘。在两个圆盘的中间，我们安装了一根细长的不锈钢丝，用于产生氢气泡。电线的电力是通过滑环供给的。利用两台CCD摄像机（一台为俯视摄像机，一台为侧视摄像机）、两台CCD摄像机的图像合成装置和录像机，可以记录气泡的三维运动行为。最后，为了验证该系统的有效性，我们模拟了两个旋转圆盘中间产生的单个气泡的运动。结果，我们认识到，该系统对于从旋转坐标系定量地观察不稳定流动是有效的，但是由于作用在气泡上的浮力，对于观察旋转轴方向上的流动是无效的。少

The unstable flow between two rotating disks has recently considered as an important research theme in connection with disk-flutter, disk-crash; thermal problems and the behavior of dusts. Only a few reports can be found on this topic because the flow is so complicated and has three dimensional structures.In this study, we developed a system for measuring three dimensional velocity fields and the frequency of the unstable flow by using hydrogen bubble method and image enhancement technique. We performed the project according to the following procedure; (1)Design and manufacturing of the experimental apparatus, (2)Design and manufacturing of the control system for driving disks, (3)Design and manufacturing of electric circuits for generating hydrogen bubbles, (4)Experiment, (5)Development of the method for image analysis, (6)Development of the software for image analysis, (7)Development of the verification method for the system developed in this study.The experimental apparatus is compo … More sed of the acrylic cylinder simulating the shroud and two parallel rotating glass disks. In the middle of two disks, we installed a slender stainless wire for generating hydrogen bubble. The electricity for the wire is supplied through a slipring. By using two CCD cameras, one is for top view and another is for side view, the device for composing the image from two CCD cameras and a video tape recorder,we could record the behavior of three dimensional bubble motions. After that by using the apparatus for image enhancement, we could trace the instantaneous three dimensional motion of bubbles.Finally, to check the effectiveness of this system, we simulated the motion of a single bubble generated just in the middle of two rotating disks. As a result, we recognized that this system is effective for observing the unstable flow from the rotating coordinate system quantitatively, but is not effective for observing the flow in the direction of the axis of rotation because of the buoyant force acting on the bubble. Less