不同沙源供给条件下砾石床面的风沙流结构与蚀积量变化风洞实验研究
不同沙源供给条件下砾石床面的风沙流结构与蚀积量变化风洞实验研究
摘要： 通过对不同沙源供给条件下各种砾石床面的风沙流结构、床面风蚀及堆积沙量变化的风洞实验,结果表明,风沙流结构是判断戈壁风沙流饱和与不饱和的一个重要途径,不同的戈壁风沙流结构对床面输、阻沙特性具有不同的指示意义.近地表0～6 cm高度内的风沙流结构决定了床面的输、阻性质,而6 cm以上的风沙流结构反映了风力对沙物质的输送状况.沙源供给的丰富与否,决定了风沙流的饱和程度,以及风沙流在砾石床面产生的蚀积状况.同等风速条件下,饱和风沙流的`输沙率是非饱和风沙流输沙率的2～8倍.在饱和风沙流情形下,床面过程总体以积沙为主,且随风力的增强,床面积沙量急剧增加.在不饱和风沙流情形下,砾石床面总体以风蚀和输送沙物质过程为主,风沙流结构在0～2 cm高度内反映出砾石床面具有明显的阻沙功能,在2～5 cm高度上出现最大输沙值. Abstract： Sand-laden wind structure and sand erosion-deposit budget over gravel bed under abundant and deficient sand supplies were studied in wind tunnel experiment. The sand-laden wind structure is a significant judge to distinguish sand-saturated structure from unsaturated one, indicating different erosion-deposit characters of gravel bed. The structure within 0～6 cm height mainly indicates the erosion-deposit characters of gravel bed, and that above 6 cm reflects the sand-transported condition by wind. Sand supply determines the saturation degree of sand-laden wind and whether the gravel bed is in erosion or in deposition. Given the same wind condition, the sand transporting rate of saturated sand stream is 2 to 8 times of that of unsaturated one. Sand deposition phenomena mainly happen in condition of saturated sand stream, and the deposited sand quantity increases sharply with the increase of wind speed. Whereas, processes of erosion and sand transportation occur in condition of unsaturated sand stream, and the stream structure within 0～2 cm height reflects the obvious sand-arresting function of gravel bed, and the largest sand-transporting rate appear within the height of 2～5 cm. 作 者： 张伟民 汪万福 张克存 柳本立 ZHANG Wei-ming WANG Wan-fu ZHANG Ke-cun LIU Ben-li 作者单位： 张伟民,张克存,柳本立,Z
汪万福,WANG Wan-fu(敦煌研究院,甘肃,敦煌,736200)
期 刊： 中国沙漠 ISTICPKU Journal： JOURNAL OF DESERT RESEARCH 年，卷(期)： 2009,29(6) 分类号： X169 关键词： 砾石床面 风沙流结构 床面蚀积 沙源供给 风洞实验 Keywords： gravel bed sand stream structure bed surface erosion and deposition sand supply wind tunnel experiment
