Speckle velocimetry study of vortex pairing in a low-Re unexcited jet

Abstract

Application of speckle velocimetry in a round jet (Re=2300) provides instantaneous 2-D velocity fields and vorticity maps of the interaction between unstable vortices. Detailed descriptions of the pairing process and of the large-scale structures observed near the end of the potential core are obtained without excitation of the jet and without the smearing effects of the conditional sampling method.