CML模型的时空混沌

提出了一类新的耦合映射格点（ＣＭＬ）模型．数值实验表明这类新的ＣＭＬ模型对于强弱耦合系统均能有效研究其时空复杂性，揭示了非线性、耗散、色散相互作用的非常丰富的时空Ｐａｔｅｒｎ行为     

CML模型和湍流的非线性

本文在现有耦合映射格点(CML)动力系统模型的基础上,提出了能够同时模拟对流项和扩散项的强弱耦合系统的CML模型,分析了这类模型的特点和结构.数值试验表明,这类CML模型能够有效地研究时空复杂性,利用数值模拟的结果对湍流的物理机制作了初步的阐释.     

Study on random and coherence states using a family of CML models

A family of coupled map lattice (CML) models has been developed to simulate the interaction of convection, diffusion and dispersion in both weakly and strongly coupled cases. With variation of parameters, the models can simulate those systems of convection dominating, diffusion dominating, and dispersion dominating states. Not only coherent and turbulent properties as well as their interrelations, but also the transitional state between any modes with local coupling and global coupling are analysed to demonstrate the essential characteristics of any state. Numerical results show that the models are capable of simulating both layered coupling and stochastic mechanism, and thus can be conveniently used to analyse an initiative and driven coupled system. Results of numerical simulation also lead us to understand whether or not turbulence coherent structure is formed by modulation of wave packet. Finally, the duality of wave and particle characters of turbulence is illustrated in the numerical simulation.     

明渠流动若干特性初探

解析定量计算了光滑边壁条件下明渠内部平均流和脉动流能量间的分配关系,得到了平均流粘性耗散能量、脉动流能量、脉动流取自平均流能量之间的关系表达式.分析了能谱的结构形式,从工程应用的角度初步勾勒了恒定流动光滑边壁条件下明渠内部能量分布的轮廓.讨论了壁面剪切流层内的流场结构和特性,研究了Navier-Stokes方程的标度变换等一些定量的指标,从标度和流速分布之间的相互关系入手,对这些指标及其间的相互关系进行了讨论.分析了二维平行壁面剪切流内部流动结构的机理和特性,指出能量传递和不同阶段的不同结构有关,能量耗散和扩散与共振和锁频密切相联系.从另一个角度阐释雷诺数的物理意义,以突出雷诺数和涡之间的关系,强调雷诺数是空间点和时间的函数.