Transport mechanisms of contaminants released from fine sediment in rivers

doi:10.1007/s10409-015-0520-8

IMECH-IR > 流固耦合系统力学重点实验室

	Transport mechanisms of contaminants released from fine sediment in rivers
	Cheng PD(程鹏达); Zhu HW; Zhong BC; Wang DZ; Wang, DZ (reprint author), Shanghai Univ, Shanghai Inst Appl Math & Mech, Shanghai 200072, Peoples R China.
发表期刊	ACTA MECHANICA SINICA
	2015-12
卷号	31 期号:6 页码:791-798
ISSN	0567-7718
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.
关键词	Cohesive Diffusion Seepage Boundary Layer Adsorption/desorption Coupling
DOI	10.1007/s10409-015-0520-8
URL	查看原文
收录类别	SCI ; EI
语种	英语
WOS记录号	WOS:000367452900002
关键词[WOS]	MACRO-TIDAL ESTUARY ; WATER INTERFACE ; MASS-TRANSFER ; SUSPENSIONS ; TURBULENCE ; DYNAMICS ; UK
WOS研究方向	Engineering ; Mechanics
WOS类目	Engineering, Mechanical ; Mechanics
项目资助者	This work was supported by the National Key Program of the National Natural Science Foundation of China (Grant 11032007)
论文分区	二类
引用统计	被引频次：12[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/58653
专题	流固耦合系统力学重点实验室
通讯作者	Wang, DZ (reprint author), Shanghai Univ, Shanghai Inst Appl Math & Mech, Shanghai 200072, Peoples R China.
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,&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.

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