【摘要】 通过对不同孔隙度尼龙网对风沙流减弱作用的风洞模拟实验,旨在探求输沙量与孔隙度和风速二者之间的关系,从而为防沙新材料的开发、野外工程防沙的优化设计及其应用提供理论依据。如果没有风蚀过程发展导致风沙流的出现,就不可能有因沙粒输送和堆积过程中引起的各种沙害。因此,防治沙害、改善沙区生态环境的根本措施还是选择合适的材料抑制或削弱风沙流的强度。而防沙材料本身又对携沙气流产生影响,如何协调二者之间的互馈关系,使得防沙材料发挥最大的防沙效益便是本文研究的目的。在前人研究的基础上,作者以平均净阻沙率、网后平均输沙率和风沙流动态变化趋势为参考指标,初步确定尼龙网防沙效益的最佳孔隙度β应该在40%左右。更多还原

【Abstract】 Though simulations on abated effect of nylon net with different porosities on wind-blown sand in wind tunnel, the aim of this paper is to research the relationship between sand transporting and nylon net porosity and wind velocity. Therefore it can provide a theoretic bases for optimized design of blown sand engineering in the field and a new sand-defending material application. Without the occurrence of wind-sand stream in the course of wind erosion, there are not any sand damages caused by sand grain initiation, transportation and accumulation. So, the basic approaches of controlling sand damages and meliorating environment in sand region is selecting appropriate materials or abate the intensity of drifting sand flux. However, the materials also reacting to the sand-laden air flow. How to harmony the relationship between sand-defending materials and the turbulence of air flow and gain extraordinary effect is the purpose of this experiment. According to mean sand transporting rate, mean net sand blocking rate and dynamic changing trend of wind-sand stream behind nylon net, the fence of porosityβ=30% was found to have highest threshold velocity, indicating a good shelter effect for abating wind-blown sand particles.更多还原