Abstract
Flow pattern of the necklace vortices in the gap space between two circular cylinders whose diameter is different forming a separated cross was visualized in the symmetrical plane under the Reynolds number of 1500. The space ratio was altered from s/d 1=0 to 2.0, and the diameter ratio was altered from d 2/d 1=0.67 to 1.5. As the results, 8-system of necklace vortices is formed in the wide range of s/d 1 and d 2/d 1. The space ratio in which the necklace vortex is formed becomes large with the diameter ratio increasing.
