矩形腔反向驱动流流型分析与数值模拟

Streamline Pattern Analysis and Numerical Simulation of Rectangular Cavity Driven Flows with Two opposite Moving Walls

研究了矩形腔双壁等速反向驱动流涡结构特性。采用非线性动力学方法,对远离边界的二维不可压缩流动线性退化奇点进行了分析,分别获得了正形四阶和正形六阶的局部流型和分岔;采用计算流体动力学方法,对不同深宽比矩形腔上下壁反向驱动低雷诺数流动进行了数值模拟,给出了涡结构演化过程中的临界深宽比、流型及其分岔图。数值模拟结果揭示出随深宽比的增加,腔内流型具有周期性和自相似性的变化特征。由鞍点和中心构成的局部流型在低雷诺数流动中是实际存在的。

Vortex structure of the two-dimensional incompressible flow in a rectangular cavity with two equal speed and opposite moving walls was considered.Streamline patterns and their bifurcations near linear degeneracy critical point away from boundaries were investigated using method from nonlinear dynamics.The local streamline patterns and bifurcation diagrams for normal forms of order four and order six were obtained respectively.Low Reynolds number flow in a rectangular cavity with two moving walls in opposite directions and different aspect ratios was numerated using computational fluid dynamics method.The critical aspect ratios,streamline patterns and bifurcation diagrams were proposed.Numerical simulation shows that the evolution of flow pattern unfolds the characteristics of periodicity and self-similarity with aspect ratio increasing.The local streamline patterns consisting of centers and saddle points can be realized in low Reynolds number flows.