Abstract
We investigated the shapes and dynamic behaviors of vortexes in a mechanically agitated water bath, focusing attention mainly on inclined-vortex formation by offset agitation that is effective for the mixing of a liquid and low density particles. The shapes of observed vortexes were classified into two groups, i.e., inclined vortexes and pseudo-vertical vortexes. The dynamic behaviors of the vortexes were classified into the following types: (1) stable, (2) intermittently developed, and (3) undeveloped vortexes. The relationship between the vortex type and geometrical conditions (i.e., the depth of the water, HW, and the height of the impeller, H) was summarized as the vortex formation map (H-HW diagram) for given bath diameter, rotation speed of the stirrer and offset distance, RE. The condition for the formation of each vortex-shape group was expressed by the corresponding equation containing geometrical parameters such as H, HW, and RE.
