摘要
本项研究利用室内水槽测量五种不同高度大米草冠层（ｃａｎｏｐｙ，指一定密度的植物群体）水流平均流速剖面。实验结果揭示了大米草冠层上、下水流的复杂性。另外，在冠层内出现流速反转梯度ｕｚ，导致一个次级流速最大值。大米草冠层上的水流切变流速ｕ大于冠层内的ｕ。冠层内水流切变流速的减小有利于粘性泥沙的沉积。大米草冠层通过影响底床剪切应力τｂ和水流紊动而对悬浮泥沙浓度、细颗粒泥沙絮凝体沉降速率产生作用。
Velocity profiles of unidirectional steady current were measured in and above five different heights of Spartina anglica canopies (350 stems m -2 ) in a flume. Results demonstrate the flow complexity in and above the various heights of the canopy. Furthermore, in the lower part of the canopy there is a reversal of the flow velocity gradient z, resulting in a secondary flow velocity maximum in the Spartina anglica canopy. The shear velocity above the canopy is larger than that within the canopy. The reduction of u * within the canopy will favor the deposition of cohesive suspended sediment. The canopy exerts a strong influence on the concentration, settling velocity of the flocs and deposition rate of the cohesive suspended sediment through effects on bed shear stress and turbulence of flow within the canopy.
出处
《泥沙研究》
CSCD
北大核心
1997年第3期82-88,共7页
Journal of Sediment Research
关键词
海岸
盐沼植物
泥沙运动
水流流速
Spartina anglica, secondary flow maximum, cohesive sediment transport, flume
