竜巻型遠隔吸引装置の流れにおけるスカート構造の検討

抄録

Flow visualization experiments with smoke and particle image velocimetry are conducted to investigate the characteristics of tornado-like swirling flow generated by a tornado-type remote suction device. We added skirt structure to the conventional flat rotating disk. In this research, several rotating disks with the skirt structures were used in the tornado generator to examine the effect of the skirt structure. The experimental parameters controlled in this flow are configuration of the rotating disk and installation height. The results obtained are as follows: When the device is installed in the higher position, the rotating disk with the skirt structure stabilize the tornado compared with the flat rotating disk. This may be due to the approaching and vertical transformation of the vortex ring surrounding the tornado-like swirling flow. When installed in the lower position, the skirt structure causes the vortex ring to disturb the bottom wall flow and weaken the vortex. It was found that a balance between the size of the vortex ring and the installation height is important to enhance the swirling flow. In addition, when installed in the higher position, the skirt structure with an outward angle enhances the swirling flow more as the skirt height increases. However, the inward skirt structure weakens the swirling flow as the skirt height increases. This seems to be due to the vortex ring being too close to the tornado-like swirling flow.