地表温度对颗粒跃移轨迹的影响

为了研究由地表温度变化引起的向上的垂向气流对沙粒跃移运动的影响,本文给出了考虑近地表温度变化和水平来流风场作用下的沙粒的跃移运动。在定量给出不同时刻的近地表温度和垂向风速的基础上,计算了由于太阳辐射所引起的近地表层垂向气流对沙粒跃移运动的影响,发现:垂向风速在午后可达到1.5m/s并使得沙粒跃移轨迹的最大高度和长度分别增加55.56%和73.68%;同时,与不考虑温度效应的情况不同的是,沙粒跃移轨道最大高度将随粒径变化。

Effect of Earth Surface Temperature on Saltation Trajectories of Sand particles

The saltation trajectories of sand particles in a horizontal wind field and a vertical wind field arising due to solar radiation are investigated to find out the influence of the temperature variation near the earth surface on the saltation movement of sand particles. Calculated the temperature near the earth surface and the upward wind speeds at different moments during a full day, the saltation trajectories of sand particles in a horizontal wind field combined with the vertical wind field are simulated. The numerical results show that the maximum height and span of the trajectories respectively increase by 55.56% and 73.68% afternoon at which the upward wind speed approaches to 1.5m/s. Moreover, when the upward wind speed is taken into account, the calculated trajectories of sand particles with individual diameters are different, which is quite distinguished from the simulation without upward wind speed.