Hiroyuki Furukawa
Graduate School of Human Informatics
Nagoya University
Furo-cho, Chikusa-ku, Nagoya
464-8601 Japan
hiroyuki@info.human.nagoya-u.ac.jp
In Taylor vortex flows developing between two concentric cylinders of finite length, the Reynolds number based on the rotation speed of the inner cylinder and the aspect ratio defined by the ratio of the cylinder length to the gap between cylinders are main parameters which determine the modes of flow. In this study, the transformation of flow modes in a decelerating Taylor vortex flow is examined numerically. The finite difference method is used to solve unsteady axisymmetric Navier-Stokes equations. At a constant aspect ratio, the flow has three modes: primary mode, normal secondary mode and anomalous secondary mode. The collapse of flow pattern from the secondary mode to the primary mode is clarified qualitatively, and the Reynolds number at which the flow mode changes is determined. In a flow with anomalous cells, extra vortices appear near the end wall of cylinders. As the rotation speed decreases, the extra vortices merge and the flow mode becomes normal. The result shows good agreement with experimental observations.