Abstract
By use of smoke-wires outside the turbulent region of a plane air jet, the entraining fluid was marked and thus the passage of turbulent large-scale structures was detected from the contortions of the turbulent-non-turbulent interface. These structures were observed to be highly three-dimensional, having considerable amount of streamwise vorticity in the trailing region. The occurrence of these structures was highly non-periodic with no detectable correlation between their occurrence across the centerline. The engulfment of the entraining nonturbulent fluid takes place predominantly in the trailing region of the coherent structures. Even though the details remain to be established, this study reveals that the large-scale coherent structures in the self-preserving region of the plane jet is highly complex.
