1017 EXPERIMENTAL STUDY ON THE SCHMIDT NUMBER DEPENDENCE OF THE SCALAR DERIVATIVE STATISTICS IN A LIQUID AXISYMMETRIC JET

抄録

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 and temperature are measured. As diffusing dyes, Acid Blue 9 and Direct Blue 86 are chosen whose Schmidt numbers are about 600 and 3,800, respectively. The Prandtl number of temperature is about 7. Experimental results show that the power spectra of the concentration fluctuation for two different diffusing dyes show some differences each other in the higher frequency region. Further, the power spectrum of the temperature fluctuation obeys -5/3 power law only in the lower frequency region than those observed in the power spectra of the concentration fluctuation. Moreover, the probability density function of the concentration fluctuation of the scalar is skewed more negatively as Schmidt number becomes higher.