Abstract
Hot-wire and flow-visualization studies have been carried out in three air jets subjected to pure-tone acoustic excitation, and the instability, vortex roll-up and transition as well as jet response to the controlled excitation have been investigated. The conditions most favorable to vortex pairing were determined as a function of the excitation Strouhal number, the Reynolds number (Re//D), and the initial shear-layer state. It is shown that the rolled-up vortex rings undergo pairing under two distinct conditions of excitation: ″the shear layer mode″ when the Strouhal number based on the intitial shear-layer momentum thickness is about 0 multiplied by (times) 012, and ″the jet column mode″ when the Strouhal number based on the jet diameter is about 0 multiplied by (times) 85. The trajectories of the vortex centers and their convection velocities during a pairing event have been recorded through phase-locked measurements. Refs.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 449-491 |
| Number of pages | 43 |
| Journal | Journal of Fluid Mechanics |
| Volume | 101 |
| Issue number | pt 3 |
| State | Published - Jan 1 1980 |
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering