| 床面形态驱动下潜流交换试验 |
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| 引用本文： | 陈孝兵,赵坚,李英玉,陈力.床面形态驱动下潜流交换试验[J].水科学进展,2014,25(6):835-841. |
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| 作者姓名： | 陈孝兵 赵坚 李英玉 陈力 |
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| 作者单位： | 1.河海大学水文水资源与水利工程科学国家重点实验室, 江苏南京 210098; |
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| 基金项目： | 国家自然科学基金资助项目(41401014;51279045)~~ |
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| 摘 要： | 为揭示河床形态特征引起的潜流交换规律,构建循环式水槽装置,通过NaCl示踪对比分析了4种河床地形驱动下的潜流交换规律,并基于扩散理论探讨了潜流交换与地表水水动力及床沙渗透特性之间的关系.结果表明,潜流交换可以发生在平坦河床地形,且交换速率随地形起伏度和雷诺数的增大而增大;在相似的地形条件下,地表流速是影响潜流交换速率的主导因素,地表水深对潜流交换速率影响较弱;此外,分析表明,有效扩散系数与河床特征粒径之间具有2次方幂率函数关系,且与河床渗透系数成正比;交换深度d正比于雷诺数Re的1/2次方.
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| 关 键 词： | 河床形态 水槽试验 潜流交换 有效扩散系数 |
| 收稿时间： | 2014-04-08 |
Experimental study of bedform-driven hyporheic exchange |
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| CHEN Xiaobing,ZHAO Jian,LI Yingyu,CHEN Li.Experimental study of bedform-driven hyporheic exchange[J].Advances in Water Science,2014,25(6):835-841. |
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| Authors: | CHEN Xiaobing ZHAO Jian LI Yingyu CHEN Li |
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| Affiliation: | 1.State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China;2.College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing 210098, China |
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| Abstract: | In order to test the bedform impacts on the hyporheic exchange behavior, the tracer NaCl is used to test the hyporheic exchanges under four groups of bedforms in a water-circling flume. Based on the diffusion theory, the impacts of hydrodynamics of water column and permeability of underlying sediments on the hyporheic flow are analyzed. Results show that the hyporheic exchanges can occur on a flat bedform. The exchange rate can be intensified under a more uneven bedform and a higher Reynolds number. Compared to the factor of water depth, the hyporheic exchange rate is much more sensitive to the velocity of the surface water. In addition, the effective diffusion coefficient is proportional to the square of characteristic grain diameter, and has a linear relationship with the streambed hydraulic conductivity. Also, the exchange depth in the flume is found to be proportional to the Re1/2. |
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| Keywords: | bedforms flume experiments hyporheic exchanges effective diffusion coefficient |
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