球形粒子の非点収差と幾何学遠近を利用した三次元粒子追跡に基づく容器内の複雑回転流れ計測の試み

抄録

Three-dimensional measurements of fluid flow using astigmatism often use microscopes in micro-scaled flows. However, three-dimensional flow measurement is necessary not only for the micro scale under microscopic observation, but also for relatively large scales. In this study, we focus on three-dimensional unsteady rotating flow driven by corotating disks in an enclosure for the purpose of observing complex fluid flow in a hard disk drive. In visualization experiments, three-dimensional particle tracking is achieved by geometric perspective based on simple size of particle image and astigmatism based on the aspect ratio or difference between vertical axis and horizontal axis of individual particle images by using cylindrical lens in the depth direction, and by in-plane position of particle image. In calibration experiments, calibration line was obtained by traversing particles on a horizontal stage. As a result, geometric perspective effect was more dominant than astigmatism effect in the depth direction. The effective area which displays relatively clear particle image in the plane of the measurement domain was also estimated. In the presentation, the performance of this method will be evaluated and its application to complex rotating flows in a container will be reported.