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

间歇性湍流的谱结构和传播机制的阐明及其控制

基本信息

批准号：
03650357
负责人：
KIKKAWA Sho
金额：
$ 1.28万
依托单位：
KINKI UNIVERSITY (1993)Toho University (1991-1992)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

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.

1.间歇湍流实验与分析对间歇振荡管流中的间歇湍流进行了测量，分析了其速度脉动。湍流区被对流到下游，由于湍流区的前导界面的通过，发生了转变。我们探测到了在前锋附近产生的大、中尺度涡旋。涡旋必须在这一转变中起主要作用。随机过程和随机场的理论和应用研究了项目所基于的随机过程的自由度(NDF)理论。阐明了NDF与Fisher信息之间的关系。结果表明：(A)第一个NDF仅仅是关于随机过程均值的Fisher信息。(B)对于AR过程，二次NDF等于关于随机过程方差的Fisher信息，证明了NDF可以解释将信号空间的维度近似为2WT值的意义，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。利用关联面积和关联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，我们进行了燃烧实验。