弱动力水流中粘性泥沙浓度沿垂线分布的研究

Experimental Study on Vertical Distribution of Cohesive Sediment Concentration in Weak Dynamical Flow

采用玻璃水槽试验方法探讨了弱动力水流条件下粘性泥沙在不同因素共同作用下浓度沿垂线的分布规律。结果表明,含沙量较小时粘性泥沙浓度的垂线分布较均匀,符合一般挟沙水流中泥沙浓度垂线分布规律。含沙量较大时,在同一水质和含沙量条件下随着流量的减小,粘性泥沙浓度的垂线分布由均匀逐渐向非均匀化发展。当流量减小到一定程度时,浓度的垂线分布出现"座椅"型的分层现象,在同一流量和含沙量条件下随着水中离子浓度的增大,泥沙浓度在近水面区减小而在近床面区增加,分层趋势进一步增强。

Based on flume experiment,this paper has studied the vertical distribution of cohesive sediment concentration in weak dynamical flow on the interaction of different conditions including discharge, sediment concentration and water quality. The results have indicated that when sediment concentration is low, the vertical distribution of cohesive sediment concentration is relatively uniform under any controlled discharge and water quality condition. This result accords with the rules in common sediment-laden flow. when sediment concentration is heavy, under the same water quality condition, the vertical distribution of cohesive sediment concentration alters from uniformity to non-uniformity depending on the decreasing of discharge. When discharge decreases to a certain value,there appears a special lamination form like a ＂chair＂ on the vertical distribution curves. And this lamination form will be improved depending on discharge＇s continual decreasing, after the lamination form comes into being, with the same discharge condition and as the increasing of ion concentration, the sediment concentration decreases in the near surface water region and increases near the bottom, resulting in further improving of the lamination form.