Clarification of the Lagrangian multi-scale mixing mechanism of High-Peclet number turbulent diffusion/reactive fields and its modeling

本研究的目的是通过实验和数值模拟来阐明高Peclet数湍流扩散/反应场的拉格朗日多尺度混合机制，并对概率密度函数(PDF)方法的数值模式进行验证和发展。为此，我们研制了三维域中速度和浓度三分量同时测量系统，并利用传统的光吸收光谱方法对基波反应扩散场进行了实验研究。在此基础上，利用随机傅里叶模态法和数值模拟方法对反应物浓度场进行了模拟。从这些实验和模拟结果中，证实了浓度统计的基本特征，并为验证PDF方法的数值模型(分子混合模型)的有效性提供了有用的数据。

The purpose of this study is to elucidate the Lagrangian multi-scale mixing mechanism of the high-Peclet number turbulent diffusion/reactive fields by the experiments and thesimulations, and to make the verification and development of the numerical models for the probability density function (PDF) method. For this purpose, we develop the simultaneous measurement system of three components of velocity and concentration in a three-dimensional domain, and also perform the experiments for the fundamental reactive diffusion field by the conventional light absorption spectrometric method. Further, the simulations of reactive concentration filed by the random Fourier modes method and DNS are performed. From these results of experiments and simulations, the fundamental characteristics of concentration statistics have been confirmed and the useful data for the verification of the effectiveness of the numerical model (molecular mixing model) for the PDF method have been obtained.