EXPERIMENTS ON THE ENTRAINMENT OF SEDIMENT INTO SUSPENSION BY A DENSE BOTTOM CURRENT
EXPERIMENTS ON THE ENTRAINMENT OF SEDIMENT INTO SUSPENSION BY A DENSE BOTTOM CURRENT
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DOI：
10.1029/92jc02404
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发表时间：
1993-03-15
影响因子：
3.6
通讯作者：
PARKER, G
中科院分区：
文献类型：
--
作者：
GARCIA, M;PARKER, G
本文叙述了密度底流挟沙成悬的试验。密度底流是通过允许盐水在基本上静止的淡水下以稳定、连续的水流运动而产生的。床斜率设定为0.08。两个等级的细粉碎的煤，与100微米和180微米的几何平均尺寸，被放置在一个槽中的床的长度为2米，在其上的密度电流通过。流速和悬浮泥沙浓度的剖面测量允许从动量和质量平衡方程反算边界剪切应力和泥沙夹带率。探讨了从边界剪应力中消除形状阻力影响的两种方法。由此产生的数据被用来比较泥沙夹带率，由于密度底流与明渠中观察到的。在现有的明渠泥沙夹带预测关系中，似乎可以进行相当适度的调整，以便预测与密度底流有关的情况。
Experiments on the entrainment of bed sediment into suspension by density underflows are described. The density underflows were created by allowing saline water to move as a steady, continuous current under a body of essentially stagnant fresh water. The bed slope was set at 0.08. Two grades of fine crushed coal, with geometric mean sizes of 100 mum and 180 mum, were placed in a trough in the bed with a length of 2 m, over which the density currents passed. Measurements of profiles of flow velocity and concentration of suspended sediment allowed for a back calculation of boundary shear stress and the rate of sediment entrainment from the equations of momentum and mass balance. Two techniques for removing the effect of form drag from the boundary shear stress were explored. The resulting data were used to compare sediment entrainment rates due to density underflows with those observed in open channels. It appears possible to make rather modest adjustments in an existing predictive relation for sediment entrainment in open channels, so as to predict the case pertaining to density underflows as well.