摘要：Distributions of velocity and concentration of turbulent gas jets, ranging from helium to carbon dioxide, with various densities with respect to ambient air are measured using particle image velocimetry and laser-induced fluorescence methods. The turbulent transport of the nozzle fluid is directly investigated to analyze the distributions of nozzle-fluid concentration and its vortex motion. The results indicate that self-similarity exists between profiles of scalar flux and Reynolds stress along the radial direction. Furthermore, several sub-grid scale scalar-flux models for large eddy simulation are discussed. Based on the scattering plots of the model values of sub-grid scale scalar flux with respect to the measured values, the characteristics of each model are similar for all of the density conditions. In addition, the Favre-averaged scale similarity model performs well for a wide range of densities.
关键词：Jet;Turbulent Mixing;Particle Image Velocimetry;Laser Induced Fluorescence;Sub-grid Scale Model
