下垫面条件对风沙活动层气流紊动性影响的风洞模拟

Wind Tunnel Simulation to Determine the Effect of Underlying Sand-laden Layer Surface Characteristics on Air Current Turbulence

通过对尼龙网格状沙障(孔隙度30%左右)、戈壁、麦草沙障和流沙地表风沙流特性的风洞模拟实验,旨在探讨不同下垫面与气流的紊动性之间的关系,以及如何影响风沙流的结构和风沙活动层的风速廓线,从而对工程防沙的优化设计提供理论依据。研究发现,对于特定的下垫面,在不同风速下同一高度层含沙量具有很大的相关性。由此可见,气流的紊动性是决定风沙活动层沙颗粒浓度分布的主要指标,也是治理沙害的一个很重要的判据。

A wind tunnel simulation of the characteristics of sand drift over a nylon net barrier with a porosity of about 30%, a grass barrier, and Gobi and mobile sand surfaces has been conducted. The aim of this paper is to describe the relationship between different underlying surfaces and air current turbulence and how characteristics of the underlying surface affect the movement of wind-blown sand and the wind velocity profile in sand-laden layers. A attempt is made to establish a theoretical base for optimizing the design of sand-control engineering in the field. This study has found that, for different underlying surfaces, there is a relationship between sand transport rate the same height above the surface at different velocities. Thus, air current turbulence can be considered as an index to determine the distribution of sand in the sand-laden layer and an important criterion determining impacts of movement.