Mixing and dispersion by a pulsating jet in cross flow

摘要

The mixing of a pulsed jet in cross-flow is studied for three frequencies by means of a coupled SPIV-PLIF measurement. In a symmetric longitudinal plane, the velocity fields result from Stereoscopic Particle Image Velocimetry (SPIV) and the concentration fields come from Planar Laser Induced Fluorescence (PLIF). In the same time, a PLIF measurement is carried out in an orthogonal plane. The studied pulsed jet is characterized by a Reynolds number Re_j = 500 based on the mean jet velocity U_j=1.67 cm/s and a velocity ratio of R = 1. A comparison between three frequencies of the pulsed jets is realized (0.25 Hz, 1 Hz, 10 Hz) with ye continuous jet. In a first step, the coupled SPIV-PLIF measurement technique is explained. Accuracy and limitations of the measurements are put forward. Secondly, the mixing processes between different pulsed jets are compared with different mixing criterions.