低层大气中固体粒子运动及其物理模拟

MOVEMENTS OF SOLID PARTICLES IN LOWER ATMOSPHERE AND ITS PHYSICAL MODELING

对于大气边界层中的固体粒子的风致运动———较大粒子的蠕动跃动和较小粒子的悬浮———的主要特征作了介绍．着重介绍了在悬浮粒子运动的物理模拟研究方面的一些成果：复杂地形和低层大气湍流会显著地提高起尘速率并改变降尘量的分布；有一定顺风向厚度的风障除了屏蔽效应———即背风侧平均风速的减小———外，还有减小最终进入空气的灰尘数量的“宏观吸附效应”；总结了模拟悬浮粒子运动的风洞实验所应遵循的相似性准则，并提出了模拟防尘风障的实验中的一个新的相似参数———孔径雷诺数，并初步测定了它的临界数值．

Movements of solid particles including creeping, salting for larger particles and suspending for smaller ones were studied. It was demonstrated that a). complex terrain and turbulence of lower atmosphere seriously increased the dust emission rate; b). windbreaks of some windward width has a “macroabsorption effect” that can reduce the ultimate dust quantity into the air as well as the usual sheltering effect, i.e., the decaying of mean wind speed in the lee side of windbreaks; c). two new similarity requests, i.e., making model dust emitting surfaces with real dust (coal, soil etc.) powders and aperture Reynolds number of windbreaks higher than a critical value, should be ensured in modeling experiments of fugitive dust movements.