VISUALIZATION OF THE LARGE-SCALE MOTION OF A PLANE JET.

The passage of turbulent large-scale structures in a plane air jet was observed from the contortions of the turbulent/non-turbulent interface made visible by the use of smoke-wire in the non-turbulent entraining flow. For the self-preserving region, these structures were found to be highly three-dimensional, displaying considerable streamwise vorticity in the trailing region. No periodicity was observed and no correlation could be detected between the occurrence of these structures across the centerline. The engulfment of the entraining non-turbulent fluid takes place predominantly in the trailing region of the coherent structures.