Abstract
A three-dimensional 'turbulent spot' has been induced in the axisymmetric free mixing layer of a 12. 7 cm diameter air jet by a spark generated at the nozzle boundary layer upstream of the exit. The spot coherent-structure signature, buried in the large-amplitude random fluctuating signal, has been educed at three downstream stations within the apparent self-preserving region of the mixing layer at the jet exit speed of 20 m s** minus **1. The eduction has been performed through digital phase averaging of the spot signature from 200 realizations. The mixing-layer spot is a large-scale elongated structure spanning the entire width of the layer but does not appear to exhibit a self-similar shape. The dynamics of the mixing-layer spot and its eduction are more complicated than those of the boundary-layer spot. This paper discusses the data acquisition and processing techniques and the results based on the streamwise velocity signals. Refs.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 65-95 |
| Number of pages | 31 |
| Journal | Journal of Fluid Mechanics |
| Volume | 98 |
| Issue number | 1 |
| DOIs | |
| State | Published - May 1980 |
ASJC Scopus subject areas
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Applied Mathematics