Regular Structures in a Plane Triple Jet

Abstract

The mixing process in the near field of a triple rectangular jet (air-CO2-air-jet) has been investigated in this paper by number density measurements (Laser-Raman-scattering) and schlieren pictures. The mixing process was found to be dominated by the rolling-up mechanism of the free shear layer into regular vortices. Four basic types of this process could be observed and are described here. Pulsed schlieren technique was applied to measure the vortex shedding frequency. The results are presented as a function of nozzle geometry and flow conditions. Finally a second vortex system oriented perpendicular to the main system could be detected.