单个天然灌丛防风阻沙机理与效应

Mechanism and Effect of Wind Break and Sand Blocking for Single Natural Shrub

天然灌丛对风沙流具有阻滞作用,以沙蒿和白刺灌丛为例,对单个灌丛周围风速及输沙量的变化进行了研究。灌丛的迎风面存在一个减速区,灌丛顶部及两侧为加速区,灌丛背风面存在一个静风区和一个尾流区。灌丛侧面的输沙量最大,背风面输沙量最小,迎风面2H处输沙量大于1H处,这与各点的风速变化是一致的。

Natural shrubs have a function of blocking wind - sand flow. Taking Nitraria sibirica Pall. shrub and Artemisia desertorum Spreng. shrub as an example, the study is carried out on the change of wind velocity and sand transportation around single shrub. The results show that there is a decelerating area on the windward side of shrub, velocity on the top and two sides of shrub is accelerated, and on the leeward side there is a standing region and a tail region. Sand transporting quantity is the most on the sides of the shrub, while it is the least on the leeward side, and the sand transporting quantity at 2H is higher than the one at 1H on the windward side, which is same with the change of sand speed at each point.