Flow visualization studies of a swirling flow in a cylinder

Abstract The three-dimensional flow dynamics of a cylindrical cyclone with tangential inlet and tangential exit with an aspect ratio of 2 and 4 was studied using flow visualization. Photographs of circular and longitudinal cross sections of the cylinder revealed stable three-dimensional flow structure in the cylinder. The primary flow was observed to follow a helical pattern that surrounded a secondary flow. The secondary flow was characterized by a single vortex that circulated around the cylinder axis and occupied a large fraction of the cylinder diameter. The secondary flow was seen to include two cells of rotation in skewed planes for an aspects ratio of 2 and four cells for an aspect ratio of 4. Qualitatively, no change in flow structure was seen for a Reynolds number of 15,000–60,000.