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NUMERICAL STUDY ON THE CHARACTERISTICS OF VORTEX FREQUENCY AND LAMINAR MIXING OF A PASSIVE SCALAR IN COAXIAL JET FLOWS  

Kim, Won-Hyun (경북대학교 대학원 기계공학부)
Park, Tae-Seon (경북대학교 기계공학부)
Publication Information
Journal of computational fluids engineering / v.14, no.3, 2009 , pp. 49-55 More about this Journal
Abstract
This study focuses on the near-field vortical structure and dynamics of coaxial jets. The characteristics of laminar flow and mixing in coaxial jets are investigated using a unsteady flow simulation. In order to analyze the geometric effects on the vortical structure, several cases of different configurations are selected for various values of the velocity ratio of inner jet to outer jet. From the result, it is confirmed that the flow mixing is promoted by the development of vortical structure and the interaction between inner jet and outer jet. This feature is strongly related to the vortex frequency in the shear-layers. The vortex frequency depends on the velocity ratio and the lip thickness of inner nozzle, but the outer pipe length has no effect on the frequency variation.
Keywords
Coaxial Jet; Mean Velocity Ratio; Vortex Structure; Vortex Frequency; Laminar Mixing; Mixedness;
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