Vortex Breakdown in a Closed Cylindrical Container with a Rotating or Stationary Conical Endwall

摘要

A visualization study is made of flow of a constant-density viscous fluid in a closed cylindrical container. Fluid motions are generated by the rotation of one of its endwalls. Vortex breakdown bubble(s) in the meridional plane are visualized by using a high-precision turntable rig. One endwall is a flat disk, and the other endwall is a cone. Cones of inclination angle α=0° (flat disk), 30°, 45°and 60° are employed in the experiment. The visualization photographs, produced by employing fluorescent dye technique, reveal the vortex breakdown characteristics. The breakdown regime diagrams in the aspect ratio-Reynolds number plots are constructed. The changes incurred in the locations and sizes of the breakdown bubble(s) are elaborated. Based on the visualized flow data, plausible physical interpretations are offered.