Trajectory Measurements of a Horizontally Oriented Buoyant Jet in a Coflow Using Filtered Rayleigh Scattering

The filtered Rayleigh scattering technique was implemented to discern the mechanisms associated with trajectory and mixing characteristics of buoyant jets in the presence of a coflow. A continuous wave laser in conjunction with a high-speed camera and a molecular filter constituted the equipment needed to obtain near-field concentration measurements of a carbon dioxide jet within a coflow of air. The arrangement enabled carbon dioxide concentration measurements with and without the coflow at a sampling rate of 400 Hz. The time-averaged results demonstrate the significance that adding the coflow has on increasing the mixing rate, thus reducing the impact of the buoyant jet by flattening the jet trajectory. The effects of various flow parameters such as the jet velocity, the jet to coflow velocity ratio, the relative velocity between the jet and the coflow, and the Froude number on the jet trajectory are studied. The downward trajectory of the carbon dioxide jet, absent a coflow, was well correlated with the Froude number. However, the addition of the coflow led to a substantial impact on the jet trajectory, reducing its buoyant effects due to a combination of increased momentum and, likely, the mixing rate. Further increases in the coflow, including the relative magnitude of the coflow, had a lesser impact. Mixing characteristics and time-dependent jet motion were captured.


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  • Accession Number: 01612586
  • Record Type: Publication
  • Files: TRIS, ASCE
  • Created Date: Jul 19 2016 3:01PM