混合层中柱状粒子取向分布函数的研究

数值模拟了平面流固混合层中柱状粒子在平面取向的分布函数，提出了描述流场中某点直粒子取向占优程度的参数Dψ的分析，说明在混合层中心区域粒子的取向排列是有序的，在混合层相邻两个大涡之间的区域，是粒子最可几角占优程度最高的地方，而且最可几取向就是沿流场的拉伸方向，说明流场的拉伸作用及方向对粒子的取向排列具有重要影响。与其它模型相比，粒子取向的分布函数模型能定量反映流场大涡对粒子取向控制的强弱程度。

Research on the Orientation Distribution Function of Cylindrical Particles in Mixing Layers

The orientation distribution function of cylindrical particle in a plane mixing layer was numerically simulated, a parameter D(?) which describes the extent of orientational preference in a plane flow field was put forward. The values of distribution function and D(?) were analyzed. The results show that the particles in the center region arrange orderly. In the region between two large scale vortices, the extent of orientational preference of the strongest and the orientations particles are identical to the direction of strain in the flow. All of these illuminate the effects of flow strain on the orientation of particles. Comparing the other models, the orientation distribution function model can reflect the influence of large scale vortices on the orientation of particles quantitatively.