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不同沙源供給條件下礫石床面的風(fēng)沙流結(jié)構(gòu)與蝕積量變化風(fēng)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(fēng)沙流結(jié)構(gòu)、床面風(fēng)蝕及堆積沙量變化的風(fēng)洞實驗,結(jié)果表明,風(fēng)沙流結(jié)構(gòu)是判斷戈壁風(fēng)沙流飽和與不飽和的一個重要途徑,不同的戈壁風(fēng)沙流結(jié)構(gòu)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(nèi)的風(fēng)沙流結(jié)構(gòu)決定了床面的輸、阻性質(zhì),而6 cm以上的風(fēng)沙流結(jié)構(gòu)反映了風(fēng)力對沙物質(zhì)的輸送狀況.沙源供給的豐富與否,決定了風(fēng)沙流的飽和程度,以及風(fēng)沙流在礫石床面產(chǎn)生的蝕積狀況.同等風(fēng)速條件下,飽和風(fēng)沙流的輸沙率是非飽和風(fēng)沙流輸沙率的2～8倍.在飽和風(fēng)沙流情形下,床面過程總體以積沙為主,且隨風(fēng)力的增強(qiáng),床面積沙量急劇增加.在不飽和風(fēng)沙流情形下,礫石床面總體以風(fēng)蝕和輸送沙物質(zhì)過程為主,風(fēng)沙流結(jié)構(gòu)在0～2 cm高度內(nèi)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(xiàn)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(xué)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(fēng)沙流結(jié)構(gòu)與蝕積量變化風(fēng)洞實驗研究】相關(guān)文章：
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