COMBINED SPIV-PLIF AND ORTHOGONAL PLIF MEASUREMENTS: MIXING IN A PULSED JET IN CROSSFLOW

摘要

A simultaneous SPIV-PLIF measurement in water is used to study a pulsed jet in a crossflow. In the longitudinal plane of symmetry of the flow, the velocity fields are measured using Stereoscopic Particle Image Velocimetry (SPIV) and the concentration fields with Planar Laser Induced Fluorescence (PLIF). At the same time, a PLIF measurement is carried out in an orthogonal plane. To take into account the PLIF error sources (spatio-temporal laser intensity variations and out-of-plane fluorescence due to SPIV particles seeding), a special data processing technique has been developed. It allows the study of mixing at an early stage of the development of a pulsed jet in a crossflow. The studied jet is characterized by the Reynolds number Re_j = 500 based on the mean jet velocity (U)_j = 1.67 cm/s, velocity ratio R=1, sinusoidal forcing amplitude ratio A_j = 2, and the stroke ratio S_r = 2.23.