二维平行壁面剪切流动的转捩与混沌模型

本文利用约化摄动方法，从理论上研究了二维平行壁面剪切流动的转捩与混沌现象，得到了描述二维平行壁面流动中的小振幅Ｔ－Ｓ波的演化方程为Ｋｏｒｔｅｗｅｇ－ＤｃＶｒｉｅｓ－Ｂｕｒｇｃｒｓ方程，反映Ｔ－Ｓ波衰减或增长率的参数为ＫｄＶ－Ｂｕｒｇｅｒｓ方程中的耗散系数Ｖ１与色散系数δ的比值ｖ１√δ，ｖ１和δ由流场结构决定的。当Ｔ－Ｓ波振幅被放大到一定程度后将受到的自由流中的高次或亚谐波的激励。经过分叉而进入混沌

The Transitional and chaotic Models of Two-dimensional Parallel Wall Shear Flows

In this paper, the transitional and chaotic phenomena in the two-dimensional parallel wall shear flows are studied using the two-dimensional reductire perturbation method. The evolution equation describing the T-S wave formed in wall shear flows is obtained. This nonlinear evolution equation is called a Korteweq-de Vries-jBurgers equation. The Grow and damp of T-S wave are determined by the parameter , where vi is called a dissipation coefficient, S is called dispersion coefficients depend the structure of flow field. When the amplitude of T-S wave grows to some extent. It will bifurcate and finall go to chaos excited by the harmonic or subharmonic disturbances in the tree streams. The bifurcation and chaotic process of two-dimensional parallel wall shear flows are described by the forced oscillation equation containing a square nonlinear term. There are two routes from periodic to chaoticmotion for T-S wave. The one is perivd doubing route. The other is even subharmome bifurcation route. From which route to chaos is determined by the exciting frequency of disturbance in free stream and the parameter v1