高Schmidt数物質噴流拡散場における速度・スカラー結合統計量(流体工学,流体機械)

概要

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In this paper, we investigate the velocity-scalar joint statistics and their Reynolds number dependence in an axisymmetric turbulent jet diffusion field of high Schmidt-number matter. The diffusing fluid is a water solution of a commercial dye (Sc≃3800), and three different issuing Reynolds numbers are chosen, i.e., 6.3×10^3, 9.5×10^3 and 1.3×10^4. Simultaneous measurements of the longitudinal velocity and concentration have been made by a combined probe of an I-type hotfilm and a fiber-optic concentration sensor. It is found that the distribution of the axial-flux probability density function (PDF) has a positive skewness, and its slope of negative tail tends to become gentle as the Reynolds number increases. The axial mean velocity conditioned by the concentration shows a good linearity to the concentration on the jet centerline. The derivative PDFs of the velocity and concentration have the exponential tails. The derivative skewness of the velocity is negative. On the other hand, the PDF of the derivative concentration shows almost symmetric distribution in the present case.
一般社団法人日本機械学会の論文
2006-11-25