Concentration flux measurements of a scalar quantity in turbulent flows

• Published in: Experiments in fluids Vol. 16; no. 3-4; pp. 273 - 281
• Main Authors: SIMOENS, S, AYRAULT, M
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.02.1994; Berlin
• Subjects: Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Instrumentation for fluid dynamics; Physics; Turbulent flow; Image processing; Particle motion; Fluorescence; Measuring methods; Velocimeters; Velocity distribution; Experimental study; Laser beams; Scalar fields; Concentration distribution
• ISSN: 0723-4864; 1432-1114
• DOI: 10.1007/BF00206547

A method for determination of velocity-concentration fluxes is presented, which combines two conventional imaging techniques, particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF). The passive concentration jet was a perfect mixture of fluorescein dye and solid particles submerged in an isotropic homogeneous turbulent channel. The light intensity fluoresced by the dye and the light intensity scattered by the particles were recorded separately on two synchronized cameras by using appropriate high and low-pass filters. Two different sets of images were thus obtained simultaneously. Once digitized and numerically processed, they provided the space and time evolution of velocity and concentration instantaneous fields. The statistical results for velocity and concentration are compared with classical results in order to validate the technique. We report some results giving velocity-concentration fluxes. (Author)