Transport mechanisms of contaminants released from fine sediment in rivers

CORC > 力学研究所 > 中国科学院力学研究所 > 流固耦合系统力学重点实验室(2012-)

	Transport mechanisms of contaminants released from fine sediment in rivers
	Cheng PD(程鹏达); Zhu HW; Zhong BC; Wang DZ
刊名	ACTA MECHANICA SINICA
	2015-12
通讯作者邮箱	dzwang@staff.shu.edu.cn
卷号	31 期号:6 页码:791-798
关键词	Cohesive Diffusion Seepage boundary layer Adsorption/desorption Coupling
ISSN号	0567-7718
通讯作者	Wang, DZ (reprint author), Shanghai Univ, Shanghai Inst Appl Math & Mech, Shanghai 200072, Peoples R China.
产权排序	[Cheng, Pengda] Chinese Acad Sci, Inst Mech, Beijing 100190, Peoples R China; [Cheng, Pengda; Zhu, Hongwei; Zhong, Baochang; Wang, Daozeng] Shanghai Univ, Shanghai Inst Appl Math & Mech, Shanghai 200072, Peoples R China
中文摘要	Contaminants released from sediment into rivers are one of the main problems to study in environmental hydrodynamics. For contaminants released into the overlying water under different hydrodynamic conditions, the mechanical mechanisms involved can be roughly divided into convective diffusion, molecular diffusion, and adsorption/desorption. Because of the obvious environmental influence of fine sediment ( 0.06 mm), non-cohesive fine sediment, and cohesive fine sediment are researched in this paper, and phosphorus is chosen for a typical adsorption of a contaminant. Through theoretical analysis of the contaminant release process, according to different hydraulic conditions, the contaminant release coupling mathematical model can be established by the N-S equation, the Darcy equation, the solute transport equation, and the adsorption/desorption equation. Then, the experiments are completed in an open water flume. The simulation results and experimental results show that convective diffusion dominates the contaminant release both in non-cohesive and cohesive fine sediment after their suspension, and that they contribute more than 90 % of the total release. Molecular diffusion and desorption have more of a contribution for contaminant release from unsuspended sediment. In unsuspension sediment, convective diffusion is about 10-50 times larger than molecular diffusion during the initial stages under high velocity; it is close to molecular diffusion in the later stages. Convective diffusion is about 6 times larger than molecular diffusion during the initial stages under low velocity, it is about a quarter of molecular diffusion in later stages, and has a similar level with desorption/adsorption. In unsuspended sediment, a seepage boundary layer exists below the water-sediment interface, and various release mechanisms in that layer mostly dominate the contaminant release process. In non-cohesive fine sediment, the depth of that layer increases linearly with shear stress. In cohesive fine sediment, the range seepage boundary is different from that in non-cohesive sediment, and that phenomenon is more obvious under a lower shear stress.
分类号	二类
类目[WOS]	Engineering, Mechanical ; Mechanics
研究领域[WOS]	Engineering ; Mechanics
关键词[WOS]	MACRO-TIDAL ESTUARY ; WATER INTERFACE ; MASS-TRANSFER ; SUSPENSIONS ; TURBULENCE ; DYNAMICS ; UK
收录类别	SCI ; EI
原文出处	http://dx.doi.org/10.1007/s10409-015-0520-8
语种	英语
WOS记录号	WOS:000367452900002
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/58653]
专题	力学研究所_流固耦合系统力学重点实验室(2012-)
推荐引用方式 GB/T 7714	Cheng PD,Zhu HW,Zhong BC,et al. Transport mechanisms of contaminants released from fine sediment in rivers[J]. ACTA MECHANICA SINICA,2015,31(6):791-798.
APA	程鹏达,Zhu HW,Zhong BC,&Wang DZ.(2015).Transport mechanisms of contaminants released from fine sediment in rivers.ACTA MECHANICA SINICA,31(6),791-798.
MLA	程鹏达,et al."Transport mechanisms of contaminants released from fine sediment in rivers".ACTA MECHANICA SINICA 31.6(2015):791-798.