尼龙网方格沙障防风效应复变规律

方格沙障的布设参数直接影响防风效应的复变作用,定量表达其复变规律,对于沙障配置模式的确定具有重要意义。在乌兰布和沙漠机械整平的风沙观测场,铺设9种不同高度、规格的尼龙网方格沙障,观测其在不同风速背景下的风速流场特征,揭示方格沙障防风效应的复变规律。结果表明:尼龙网方格沙障防风效应复合变化受不同指示风速下,沙障高度与规格共同的影响。沙障内部0. 1 m高度的风速随防护宽度的增加呈对数函数递减,指示风速增大1 m·s~(-1),风速衰减率增加0. 07倍;沙障高度增大0. 1 m,风速衰减率增加0. 20倍;方格边长增大1 m,风速衰减率减小0. 07倍。观测的9种规格方格沙障,30 cm高度1 m×1 m规格沙障复变作用最强,15 cm高度2 m×2 m规格沙障复变作用最弱。该结果可为确定沙障合理防护宽度、节约沙障铺设成本、优化沙障布设技术提供基础数据和理论支撑。

Compound Rules of Windproof Effect of Nylon Grid Sand Barrier

Nine kinds of nylon grid barriers with different heights and sizes were laid in the wind-blown sand observation filed in the Ulanbuh Desert. The characteristics of wind-flow field under different wind speeds and the compound rule of windproof effect of sand barriers were revealed. The results showed that the compound change of windproof effect of grid sand barriers was affected by the height and size of sand barrier under different wind speeds. The wind speed at 0.1-m height near the sand barrier was decreased logarithmically with the increase of windproof width, which indicated that the attenuation rate of wind speed near the sand barrier was increased by 0.07 times when the wind speed increased by 1 m·s^-1; it was increased by 0.2 times when the height of sand barrier was increased by 0.1 m; and it was decreased by 0.07 times when the length of grid side was increased by 1 m. Among the nine kinds of grid sand barriers observed, compound effect of 1 m×1 m sand barrier with 30-cm height was the highest, but that of 2 m×2 m sand barrier with 15-cm height was the lowest. The results could provide the basic data and theoretical support for determining the reasonable windproof width of sand barrier, saving the layout cost of sand barrier, and optimizing the technology of sand barrier layout.