【摘要】 直立栅栏作用于地表深刻地影响了周围气流的流动特性,使原来流经地表的气流成为一种特殊形式的"次生流"。根据PIV所测的非对数-线性风速廓线形态及风速廓线所表现的不同速度梯度,栅栏周围的流场可以划分为6个典型区域。随着栅栏疏透度的增加,流动的区域会随着下风向距离的增加逐渐合并,划分的区域越来越少。这些典型的区域分别表现了气流的不同运移行为及能量传输特征,对栅栏周围的风沙沉积有很大的影响。更多还原

【Abstract】 Upright porous fence affected the flow characteristics deeply when it acts on the ground,which makes the airflow to be a kind of typical form secondary flow.Based upon the overall non-log-linear velocity profiles,six typical flow layers or regions can be roughly identified characterized by different velocity gradients.The airflow becomes less complicated and the number of flow regions decreases as fence porosity increases.The flow regions gradually merge as the distance downwind increases,and eventually recover a single velocity profile due to downward transfer of momentum from overlying layers.These typical flow regions represent different flow behavior and momentum and kinetic energy transport process,which affected the eolian sand deposition around fences.更多还原