Research on the influence of urban environment to the Japanese cedar pollen resuspension and exposure phenomena

本文讨论了日本杉花粉在城市冠层中的悬浮行为及其数值预报方法，大部分花粉在城市冠层外缘附近飞行，但由于高层建筑物的阻挡，风和飞行的花粉很少进入这一层。花粉进入城市冠层后，会在该层的底部重新悬浮，用Euler-Euler方法和单向耦合相结合的方法预测了没有重新悬浮的花粉悬浮行为，但如果没有粒子之间或粒子与物体之间的碰撞，则无法预测花粉粒子的重新悬浮。为提高计算精度，提出了正交贴体曲线坐标系。

We discussed about the suspension behavior of the Japanese cedar pollen in the urban canopy layer and the numerical prediction method of this behavior.Much pollen flies around the outer edge of the urban canopy layer, but less pollen flies into this layer because the high buildings block the wind and the flying pollen. The pollen which flies into the urban canopy layer, is re-suspended on the bottom of this layer.The pollen suspension behavior without re-suspension is predicted with a combination of Euler-Euler method and 1 way coupling, but the resuspension of the pollen particles can not be predicted without the collision between particles or between particles and objects. Orthogonal body-fitted curvilinear coordinate system is proposed to improve the calculation accuracy.