椭球度对层状球形液滴光学焦散结构的影响

Influence of Aspect Ratio on Optical Caustic Structure of Layered Spherical Droplets

利用矢量光线追踪模型模拟了光线进入双层球形液滴和双层椭球液滴的传播过程。利用一阶彩虹区域相同方向出射光线数目变化的边界,得到了彩虹条纹和双曲脐条纹。双层球形液滴只有彩虹条纹,而双层椭球液滴既有彩虹条纹,也有双曲脐条纹。随着椭球度的增大,彩虹条纹的曲率先增大后减小,双曲脐条纹先向着散射角减小的方向移动,再向着散射角增大的方向移动。发现的规律可应用于双层液滴形状测量。

Vector ray tracing model is used to simulate the propagation of light into a single-layer spherical droplet and a single-layer oblate droplet.Rainbow fringe and hyperbolic umbilic fringe are obtained by using the boundary of the number of outgoing rays in the same direction in the primary rainbow region.Single-layer spherical droplets have only rainbow fringe,which is independent of droplet size when the core-shell ratio is constant,while single-layer oblate droplets have both rainbow fringe and hyperbolic umbilic fringe.With the increasing of aspect ratio,the curvature of the rainbow fringe increases first and then decreases.The hyperbolic umbilical fringe moves first in the direction of decreasing scattering angle,and then in the direction of increasing scattering angle,which can be used to measure the shape of single-layer droplets.