抄録
Experimental study was carried out on the vortex breakdown in a cylindrical container with free surface. Swirling flow was driven by the rotation of the bottom endwall disk. Meridional flow was visualized by means of the fluorescein sodium dye technique. Various formations of one axis bubble, two axis bubbles, one axis bubble attached to the free surface, two axis bubbles with the upstream one attached to the free surface, ring vortex etc. were observed. Critical boundaries for various type vortex breakdowns and boundary between steady and unsteady flows were also shown for the combination of Reynolds number based on the rotation of the bottom endwall and the aspect ratio of the depth of working fluid to the radius of the container. Comparison with the previous experimental and numerical results is discussed.
