湍流相干结构的速度与温度特性

本文采用三分量热线同时测量温度和速度的新技术，测量了加热与制冷平板边界层的速度和温度分布，提出了提取相干结构的雷诺应力准则，根据湍流相干结构速度与温度的相关关系，运用子波分析方法首次确定了相干结构的温度特征尺度和波形。对于研究湍流结构相干结构的速度与温度特性，具有重要的意义。此外，本文还应用数字滤波方法对所分析的湍流相干结构进行了滤波处理，确定了相干结构的平均猝发周期，与条件采样方法相比，两者的结果基本一致。本文实验分析结果还表明：壁面温度对湍流相干结构有一定的影响。

The Velocity and Temperature Properties of Coherent Structure in Turbulence

A new measuring technique with three-component hot wire for measuring velocity and temperature in flow field at the same time was used to measure the distribution of velocity and temperature in the boundary layer of heated and cooled plates. The maximum Reynolds stress criterion was proposed. Based on the relationship between the velocity and temperature of coherent structure, wavelet method was used to determine the temperature characteristic scale and profile, which is significant for investigating the velocity and temperature coherent property in turbulence. Meantime, the digital filter method was used to process the coherent structure obtained. The mean bursting period was also gained. The result agrees well with the value from conditional sampling method. The results also indicated that the wall temperature had some effect on the turbulent coherent structure.