減速するテイラー渦流れにおけるモード変化

抄録

For Taylor vortex flows developing between two concentric cylinders with finite length, the Reynolds number based on the rotation speed of the inner cylinder and the aspect ratio defined by the cylinder length and the gap between cylinders are dominant parameters which determine modes of flow patterns. In this study, the flow modes in decelerating flow are 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 mode. The qualitative process of flow pattern exchange from the secondary mode to the primary mode is revealed and the Reynolds numbers at which flow modes change are determined. In the flow with anomalous cells, extra vortices near the end wall of cylinder merge and make the flow mode normal. The result shows good agreement with experimental observations.