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

探讨了雪松花粉在城市冠层中的悬浮行为及其数值预报方法，结果表明，在城市冠层外缘附近飞入的花粉较多，而进入该层的花粉较少，因为高楼遮挡了风和花粉的飞扬。采用欧拉-欧拉法和单向耦合相结合的方法预测了无再悬浮的花粉悬浮行为，但如果没有颗粒间的碰撞或颗粒与物体之间的碰撞，则不能预测花粉颗粒的再悬浮。为了提高计算精度，提出了正交化贴体曲线坐标系。

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.