G0903 Study on the Schmidt number dependence of the high order statistics of concentration of diffusing matters

Abstract

In this study, the dependence of the scalar statistics on the Schmidt number is investigated experimentally in a liquid axisymmetric jet. In this experiment, the concentration of two diffusing dyes is measured by means of the light absorption method. As diffusing dyes, Acid Blue 9 and Direct Blue 86 are chosen whose Schmidt numbers are about 600 and 3,800, respectively. Experimental results show that the slope of the power spectrum of the concentration fluctuation of Direct Blue 86 is gentler than that of Acid Blue 9 in the high frequency region. Moreover, the probability density function of the concentration fluctuation is skewed more negatively as Schmidt number becomes higher.