| 刘金梅,王士强,王光谦.冲积河流长距离冲刷不平衡输沙过程初步研究[J].水利学报,2002,33(2):0047-0054 |
| 冲积河流长距离冲刷不平衡输沙过程初步研究 |
| A study on non-equilibrium sediment transport process of long distance erosion in fluvial river |
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| DOI： |
| 中文关键词: 表层床沙相比 不平衡输沙 床沙交换速率 |
| 英文关键词: coarsening river bed surface material non-equilibrium sediment transport exchange rate of bed material |
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| 中文摘要: |
| 本文从悬移质扩散方程出发, 研究冲积河流长距离冲刷不平衡输沙过程. 对于天然沙质河流, 床沙均为非均匀沙, 由于较细泥沙的冲刷率总大于较粗泥沙, 因此在床面薄层内泥沙随冲刷迅速粗比, 致使挟沙力降低, 不平衡输沙距离比均匀沙情况大大延长. 文中同时提出了表层床沙粗化的概化计算模式及床沙交换速率计算公式. 床沙交换速率的大小是决定含沙量恢复饱和距离的重要因素. 本文对不同类型底部边界条件进行了计算比较, 并与黄河下游的实际冲刷资料进行了对比, 结果表明, 应用梯度型底部边界条件, 且在考虑表层床沙粗化中以作者提出的公式计算床沙交换速率, 则计算含沙量和实际符合良好. |
| 英文摘要: |
| Based on the diffusion equation for sediment, the transport process of long distance erosion in fluvial river is studied. It is found that the distance of non-equilibrium sediment transport in natural river is much longer than that of river bed with uniform sediment, since the bed surface is coarsened in the process of erosion and the scouring will be weakened. A model for calculation of bed material on coarsened surface and a formula for bed material exchange rate are proposed. The exchange rate is an important factor in determining the erosion distance of non-equilibrium sediment transport. The calculation results for different kind of river bed condition and the comparison with observation data show that goodagreement is achieved if constant entrainment flux is assumed and the exchange rate formula proposed by the authors is adopted. |
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