波浪作用下涡动沙纹床面的悬沙运动数值研究

Numerical study on suspended sediment movement in wave boundary layers over rippled bed

作者建立了波浪作用下的立面二维水沙数值模型,并对涡动沙纹床面的悬沙运动进行研究。结果表明:悬沙颗粒的沉降速度较小时,其运动受到涡动力特性的影响比较显著。而且在沙纹波峰断面和沙纹波谷断面,半个周期里都可以观察到两个悬沙分布的峰值,主要是由于流动分离形成分离涡,涡运动携带泥沙颗粒而出现峰值。计算成果在一定程度反映了涡动结构对悬沙运动的影响。

The authors established a model of the distribution of suspended sediment by means of a 2D numerical model.For a large settling velocity,the suspended sediment was confined to the vicinity of the bed and its suspension patterns were dominated by local bottom shear stress.For a small settling velocity,the suspension was controlled mainly by the characteristics of vortex.Two suspended sediment movement peaks were observed in the crosssection at the trough and crest during the half period with the second peak being due to the separation bubble taking up the sediment.