定常对称背涡流态下细长体绕流结构的演变

Structure evolution of the steady and symmetric vortex pattern around a slender

应用数值计算的方法模拟了细长体截面绕流结构的演变过程 .指出随着细长体背涡的发展 ,导致截面流场的拓扑结构发生变化 ,会出现一种临界流动状态 .并用微分方程的定性理论分析了此时流场中出现的一种高阶奇点 .这种高阶奇点的指数为 - 3 2 ,它是结构不稳定的 ,稍有扰动就会产生分叉 ,使流场的拓扑结构发生变化 .得出了定常对称背涡流态下细长体的空间绕流结构图 .

The structure evolution of flow pattern around a slender was calculated by numerical method. It was pointed that the development of slender vortices leads to the change of topological structure about cross flow, and a critical flow pattern will appear. A high-order singular point in this flow field was analysed by differential equation qualitative theory. The index of the high-order singular is -3/2. The topological structure of this singular point is instable, so bifurcation will be occurred and the topological structure of flow field will be changed by little disturbance. The 3-dimensional flow structure of the steady and symmetric vortices pattern around a slender was gained.