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

Abstract

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.

Keywords

• vortex breakdown
• bubble-type
• conical endwall
• flow visualization
• ldv measurement