风扬沙环境下风沙流场风洞试验研究

通过风沙风洞试验模拟风吹床面沙环境，对不同风洞控制风速和不同沙尘粒径条件下风沙流场内沙浓度垂向分布特性比较得知:沙浓度的大小分布与沙粒径、控制风速以及高度均相关；同种粒径沙供沙床面情况下，风速越大，相同位置处的沙浓度越大，沙浓度随风速的增大而增大，随高度的增加呈指数递减；同一高度位置在相同风速下，粗沙、细沙、混合沙的沙浓度依次增大。获得床面供沙风速剖面只在高于沙床面约0.3m的范围内发生变化，相比于净风，有沙床面此高度范围内的风速小于净风速。在沙粒跃移层内，三种粒径沙对风速都有明显的削弱作用，对湍流强度却有明显的增强作用，且其显著程度与各自沙浓度的垂向分布特征有直接关系，都随着沙浓度的变化同时增大或减小。

Wind tunnel test on wind-sand flow under blowing sand environment

By simulating different conditions of wind blowing sand in wind tunnel test, the vertical distribution characteristics of sand consistency in wind-sand flow under various wind speed and particle size of sand were analyzed.It is found that the consistency of sand is dependent on particle size of sand，the wind speed and the height. When the size of sand particles is controlled, consistency of sand from the same height increases as wind speed increases. Moreover, for the same wind speed as well as the same particle size, sand consistency decreases exponentially with the increase in height. Different types of sands were also compared. It is found that with the same wind speed and at the same height, consistency of coarse sand, silver sand and the mixture of both increase in turn. In terms of the comparison of wind speed with and without sand, it is found that wind velocity profile with sand at different heights is lower than its counterpart. However, this pattern is only observed within 0.3 meters from the sand surface. Within this range, all the three types of sand can reduce the wind speed and enhance turbulence intensity and the effects are decreased with the consistency of sand.