雨强和糙度对坡面薄层流水动力学特性的影响

发布时间：2019-02-23 20:48

【摘要】：基于流体力学和水力学基本理论,通过6个糙度、5个流量和5种雨强组合条件下的放水冲刷和模拟降雨试验,研究雨强和糙度对坡面流水动力学特性的影响。结果表明:在坡面薄层水流中,床面糙度对坡面流阻力有"增阻"效应,但在粗糙尺度为1.77 mm时产生拐点;降雨条件下,坡面流自由表面失稳的动态演化过程显著,其波动临界条件为黏深比0.382 4、0.599 3,在整个动态过程中阻力系数都随着降雨强度增加而减小;结合黏滞阻力、雨强阻力构建层流过渡区阻力计算公式,决定系数为0.92(P0.05),可以较好地为坡面流模型的建立提供参考依据。研究成果有助于从泥沙运动力学的角度揭示坡面流层流失稳的本质,为坡面流理论的发展奠定基础。
[Abstract]:Based on the basic theory of hydrodynamics and hydraulics, the effects of rainfall intensity and roughness on the hydrodynamic characteristics of the slope surface were studied by the combination of 6 roughness, 5 flow rates and 5 rainfall intensities. The results show that the roughness of the bed surface has an "increasing drag" effect on the flow resistance in the thin layer flow on the slope surface, but inflection points occur when the rough scale is 1.77 mm. Under the condition of rainfall, the dynamic evolution of free surface instability of slope flow is remarkable, and the critical condition of fluctuation is that the ratio of viscosity to depth is 0.382 ~ 0. 599 3, and the resistance coefficient decreases with the increase of rainfall intensity. The calculation formula of laminar flow transition zone resistance was constructed with viscous resistance and rain intensity resistance. The determination coefficient was 0.92 (P0.05), which could provide a reference for the establishment of slope flow model. The research results are helpful to reveal the essence of laminar flow instability in slope flow from the point of view of sediment movement mechanics and lay a foundation for the development of slope flow theory.
【作者单位】：陕西省土地工程建设集团有限责任公司黄河西岸土地整治分公司;西北农林科技大学水利与建筑工程学院;西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室;中国水利科学研究院流域水循环模拟与调控国家重点实验室;
【基金】：国家自然科学基金项目(51579214、51209222、41001159) 国家973计划课题(2015CB452701) 流域水循环模拟与调控国家重点实验室开放基金(IWHR-SKL-2014) 黄土高原土壤侵蚀与旱地农业国家重点实验室主任基金(A314021402-1619)
【分类号】：S157.1

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