热混合层中温度脉动的分形特性

Fractal Properties of Fluctuating Temperature in Thermo Mixing Layer

运用计盒维数方法对测量热混合层所得到的温度脉动时间系列信号进行了详细研究，对等温界面（ｉｓｏｔｈｅｒｍｉｎｔｅｒｆａｃｅ）截取时间点集合的分形维数Ｄ＝ｌｏｇ（Ｎ（ｒ））／ｌｏｇｒ在一定的尺度范围内进行了估算，界面阀值温度范围为Ｔ±１．５Ｔ′（Ｔ，Ｔ′为测量点的平均温度和脉动温度），发现对同一热混合层垂直面的不同测量点存在相同的Ｄ＝０．３５±０．

Fractal box counting dimension method( D =log (N(r))/1/r)) is used to analyse temperature time series data measured in thermo mixing layer.When threshold of interface varies at range of ±1.5T′(,T′ is mean temperature and fluctuating temperature)there exists the same fractal dimension of isotherm interface D=0.35±0.08 at different location of same vertical surface.