轴对称射流中涡运动的三维涡丝模拟

Three-dimensional Vortex Filament Simulations of Vortex Motion in an Axisymmetric Jet

用三维涡丝法对轴对称不可压射流进行了数值模拟 ,描述了轴对称射流在外加扰动下产生的拟序结构随时间的发展 .文中应用了涡丝的增加与合并技术 ,模拟了在基波扰动作用下涡的卷起 ,以及在扰动中加入次谐波后涡的配对 .通过对不同时刻涡量图的比较与分析 ,说明扰动中的基波导致涡的卷起 ,次谐波控制着涡的配对 。

The three dimensional vortex filament method is adopted to simulate an axisymmetric incompressible jet. The temporal evolution of the coherent structures induced by axisymmetric perturbations is investigated. In the paper, the addition and amalgamation techniques for vortices are used to simulate the vortex roll up induced by the fundamental perturbation and the vortex pairing induced by the subharmonic perturbation. By comparing and analyzing the vorticity at different times, it is observed that the roll up and pairing of vortices are determined by the fundamental perturbation and the subharmonic one respectively. The conclusions are in good agreement with theoretical and experimental results.