简介:We consider the effects of the mixing conditions at the nozzle, on the mixing
in a circular impinging jet. Two situations are considered: the completely premixed tracer
or a locally injected tracer. The local instantan简介:We consider the effects of the mixing conditions at the nozzle, on the mixing
in a circular impinging jet. Two situations are considered: the completely premixed tracer
or a locally injected tracer. The local instantaneous concentration field is determined by
using Planar Laser-Induced Fluorescence (PLIF) technique. The premixed injection
variant reveals the mixing effects of the outer shear layer, while the local mixing approach
helps in understanding how to utilize the local injection for controlling the mixing of a
scalar in an impinging jet. The concentration statistics and the mixing properties indicated
by concentration probability density function (PDF) with the two injection methods are
presented. The results show the well-known structural features in the turbulent impinging
jet, the nature of mixing varies significantly in different regions of the jet. In the jet core
region and the impingement region, the mixing is dominated mainly by the large-scale
coherent structure, while in the mixing layer and wall jet region, both the large-scale
structure and small scale turbulence control the mixing.详细>