CLARIFICATION OF SPECTRAL STRUCTURE AND PROPAGATION MECHANISM OF AN INTERMITTENT TURBULENCE AND ITS CONTROL

1. 间歇式湍流的实验与分析对间歇式振荡管流中发生的间歇式湍流进行了测量，并对其速度波动进行了分析。湍流区向下游对流，过渡是由于湍流区前缘界面的通过而发生的。我们检测到在锋面附近产生了大中型涡旋。这些涡流必须在过渡中发挥重要作用。随机过程和随机场的理论与应用研究了作为项目基础的随机过程的自由度数（NDF）理论。澄清了NDF与Fisher信息之间的关系。研究结果如下：(a)第一个NDF只是关于随机过程均值的费雪信息。(b)对于AR过程，第2 NDF等于随机过程方差的Fisher信息。证明了NDF可以解释信号空间维数近似于2WT的意义。我们从NDF的思想推导出随机场的相关面积和相关长度。这些都是随机场的重要特征。利用相关面积和相关长度对可视化湍流场进行了分析。燃烧实验研究为了研究燃烧对湍流的影响，我们进行了一些燃烧实验。

1. Experiments and analysis of intermittent turbulenceIntermittent turbulence which occurred in an intermittent oscillatory pipe flow was measured and fluctuations in velocity was analyzed. Turbulent regions are convected downstream and the transition occurred as a result of the passage of the leading interface of a turbulent region. We detected large and medium scale eddies generated near the leading front. The eddies must play a major role in the transition.2. Theory and applications of a random process and a random fieldThe theory of the number of degrees of freedom (NDF) of a random process on which the project is based was investigated. The relation between the NDF and Fisher information was clarified. The results are as follows ; (a)The first NDF is nothing but the Fisher information about mean of the random process. (b)For the AR process, the 2nd NDF is equal to the Fisher information about the variance of the random process.It was proved that the NDF can explain the significance of the approximating the dimension of the signal space to 2WT.We deduced correlation areas and correlation lengths of a random field from the idea of the NDF.These are important characteristics of the random field. A visualized turbulent field were analyzed by using the correlation areas and the correlation lengths.3. Experimental study of combustionIn order to study the effect of combustion on the turbulence, we performed some experiments on combustion.