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不同沙源供給條件下礫石床面的風沙流結構與蝕積量變化風洞實驗研究
摘要： 通過對不同沙源供給條件下各種礫石床面的風沙流結構、床面風蝕及堆積沙量變化的風洞實驗,結果表明,風沙流結構是判斷戈壁風沙流飽和與不飽和的一個重要途徑,不同的戈壁風沙流結構對床面輸、阻沙特性具有不同的指示意義.近地表0～6 cm高度內的風沙流結構決定了床面的輸、阻性質,而6 cm以上的風沙流結構反映了風力對沙物質的輸送狀況.沙源供給的豐富與否,決定了風沙流的飽和程度,以及風沙流在礫石床面產生的蝕積狀況.同等風速條件下,飽和風沙流的輸沙率是非飽和風沙流輸沙率的2～8倍.在飽和風沙流情形下,床面過程總體以積沙為主,且隨風力的增強,床面積沙量急劇增加.在不飽和風沙流情形下,礫石床面總體以風蝕和輸送沙物質過程為主,風沙流結構在0～2 cm高度內反映出礫石床面具有明顯的阻沙功能,在2～5 cm高度上出現最大輸沙值. 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： 張偉民 汪萬福 張克存 柳本立 ZHANG Wei-ming WANG Wan-fu ZHANG Ke-cun LIU Ben-li 作者單位： 張偉民,張克存,柳本立,ZHANG Wei-ming,ZHANG Ke-cun,LIU Ben-li(中國科學院,寒區(qū)旱區(qū)環(huán)境與工程研究所,敦煌戈壁荒漠生態(tài)與環(huán)境研究站,甘肅,蘭州,730000)汪萬福,WANG Wan-fu(敦煌研究院,甘肅,敦煌,736200)
【不同沙源供給條件下礫石床面的風沙流結構與蝕積量變化風洞實驗研究】相關文章：
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