Enhancement of the mixing and diffusion in a turbulent jet focused on the flapping phenomena and turbulent/non-turbulent interface

点击翻译按钮获取中文摘要

In this study, for the enhancement of the mixing and diffusion in a turbulent jet, the role and effect of a large-scale coherent vortex structure in a plane turbulent jet, which is intermittently observed and called "flapping motion", and the structure of turbulent/non-turbulent interface are investigated experimentally. The experiment is performed by simultaneously measuring the velocity and pressure in the self-preserving region of the jet. Experimental results show that the arising of the flapping motion enhances the diffusion of the scalar (heat), momentum, and turbulent energy to the outer side of the jet. Further, it also causes the change of the structure of the turbulent/non-turbulent interface. The controlling of the flapping motion is also performed by generating the pressure waves with using a small speakers. The results show that the arising interval and duration of the flapping motion can be controlled by the pressure waves.