脉动压力的紊流分形特征

Fractal Feature in Turbulent Fluctuation Pressure

摘要: 通过对脉动压力信号时间序列的分析证实了紊流的分形特征.首先,计算脉动压力信号时间序列的关联维数,并将其与动力系统相空间中图形结构的维数联系起来.分析表明,关联维数D_C随嵌入空间维数的不断增大而逐渐趋于定值6<D_C<7,从而证明了相空间中稳定、低维吸引子的存在,也即证明了紊流内在有序性的存在.其次,用线截法从压力信号推求等压面的维数,发现等压面维数随不同压力值的分布与压力脉动的概率密度分布一致,概率密度越大,等压面维数也越高,且等压面的分形特性是局部存在的.

Abstract: The turbulence Fractal feature is confirmed by analyzing two turbulent fluctuation pressure tem poral signals.Firstly,the correlation dimension of the turbulent fluctuation pressure temporal signal had been calculated and connected with the dimension of the figure structure drawn in the phase space of the dynamic system.The calculated results show that the correlation dimension D_C is tended to a