超声速混合层发展情况的非线性时间序列分析

采用大涡模拟数值方法,模拟了具有工程应用背景的二维超声速湍流混合层,通过非线性时间序列分析伪相图、关联维数和Lyapunov指数,得到了混合层发展情况的混沌特性.结果表明,混合层中心线沿流向位置的压力伪相图可定性地表示混合层的稳定性,关联维数分布可定量描述混合层经历的线性失稳、非线性失稳和涡合并阶段等发展情况,最大Lyapunov指数分布作为关联维数分析结果的验证.对于相应的超声速混合层实验,采用非线性时间序列分析方法研究混合层发展情况具有通用性.

Non-linear Time Series Analysis of Evolution Status of Supersonic Mixing Layer

Coherent structures of two-dimensional supersonic turbulent mixing layer with engineering background are investigated by using the method of Large Eddy Simulation (LES). Chaos characteristics of evolution status are obtained by the non-linear time series analysis of pseudo-phase portrait, Lyapunov exponent and correlation dimension. The results show that the pseudo-phase portrait of pressure can denote the stability of mixing Layer. The distribution of correhtion dimensions can be used to measure the evolution status of mixing layer quantificationally, and the distribution of maximal Lyapunov exponents can be used to validate the measure results above. In corresponding experiments for mixing layer, the universality of studies on evolution status of mixing layer by the method of non-linear time series analysis is testified.