The concentrations of the particulate organic carbon (POC) and its isotopic compositions inthe freshwater in the lower reaches of the Huanghe River were observed for one year period.The annualfluxes of the POC and tot...The concentrations of the particulate organic carbon (POC) and its isotopic compositions inthe freshwater in the lower reaches of the Huanghe River were observed for one year period.The annualfluxes of the POC and total carbon of the Huanghe River entering seas were estimated,in combination withthe available data on carbon in the dissolved state in literature.For this study 295 water samples and 115sediment ones from 118 stations were collected on three separate cruises to the Huanghe Estuary and morethan 400 organic carbon isotope data were obtained.After the comprehensive study a new model was con-structed on the dispersion of fine-grained suspended matter entering seas from the Huanghe River in combi-nation with contents of suspended matter,concentrations of POC in water samples and grain size parame-ters,contents of organic carbon in sediment samples.展开更多
Aquatic vegetation plays an important role in the flow structure of open channels and thus changes the fate and the transport of sediment. This article proposes a three-dimensional turbulence model by introducing vege...Aquatic vegetation plays an important role in the flow structure of open channels and thus changes the fate and the transport of sediment. This article proposes a three-dimensional turbulence model by introducing vegetation density and drag force into the control equations of water flow in the presence of vegetation. The model was used to calculate the impacts of submerged vegetation on the vertical profiles of longitudinal flow velocities, the changes of the depth-averaged flow velocities in a compound channel with emergent vegetation in the floodplain, the removal of suspended sediment from the channels by emergent vegetation, and the bed changes around and in a vegetated island. Numerical investigations show that aquatic vegetation retards flow in the vegetation zone, reduces the sediment transport capacity, and contributes to erosion on both sides of the vegetated island. Calculated results agree well with experimental results.展开更多
An algorithm to compute three-dimensional sediment transport effect was proposed in this paper to enhance the capability of depth-averaged numerical models. This algorithm took into account of non-uniform distribution...An algorithm to compute three-dimensional sediment transport effect was proposed in this paper to enhance the capability of depth-averaged numerical models. This algorithm took into account of non-uniform distributions of flow velocities and suspended sediment concentrations along water depth, it significantly enhanced the applicability of 2D models in simulating open channel flows, especially in channel bends. Preliminary numerical experiments in a U-shaped and a sine-generated experimental channel indicate that the proposed method performs quite well in predicting the change of bed-deformation in channel bends due to suspended sediment transport. This method provides an effective alternative for the simulations of channel morphodynamic changes.展开更多
基金国家自然科学基金重点项目(U1202232)国家自然科学基金项目(41061010)+3 种基金“十二五”国家科技支撑计划重大项目(2010BAE00739)The Key Project of National Natural Science Foundation of China,No.U1202232National Natural Science Foundation of China,No.41061010National Key Technologies R&D Program of China during the 12th Five-year Plan Period,No.2010BAE00739
基金the National Natural Science Foundation of China.
文摘The concentrations of the particulate organic carbon (POC) and its isotopic compositions inthe freshwater in the lower reaches of the Huanghe River were observed for one year period.The annualfluxes of the POC and total carbon of the Huanghe River entering seas were estimated,in combination withthe available data on carbon in the dissolved state in literature.For this study 295 water samples and 115sediment ones from 118 stations were collected on three separate cruises to the Huanghe Estuary and morethan 400 organic carbon isotope data were obtained.After the comprehensive study a new model was con-structed on the dispersion of fine-grained suspended matter entering seas from the Huanghe River in combi-nation with contents of suspended matter,concentrations of POC in water samples and grain size parame-ters,contents of organic carbon in sediment samples.
基金the National Basic Research Program of China (973 Program, Grant No. 2006CB403302)the National Natural Science Foundation of China (GrantNo.50779006)
文摘Aquatic vegetation plays an important role in the flow structure of open channels and thus changes the fate and the transport of sediment. This article proposes a three-dimensional turbulence model by introducing vegetation density and drag force into the control equations of water flow in the presence of vegetation. The model was used to calculate the impacts of submerged vegetation on the vertical profiles of longitudinal flow velocities, the changes of the depth-averaged flow velocities in a compound channel with emergent vegetation in the floodplain, the removal of suspended sediment from the channels by emergent vegetation, and the bed changes around and in a vegetated island. Numerical investigations show that aquatic vegetation retards flow in the vegetation zone, reduces the sediment transport capacity, and contributes to erosion on both sides of the vegetated island. Calculated results agree well with experimental results.
基金Project support by the National Natural Science Foundation of China (Grant No: 50479034), the Natural Science Foundation of Tianjin (Grant No: 05YFSZSF02100).
文摘An algorithm to compute three-dimensional sediment transport effect was proposed in this paper to enhance the capability of depth-averaged numerical models. This algorithm took into account of non-uniform distributions of flow velocities and suspended sediment concentrations along water depth, it significantly enhanced the applicability of 2D models in simulating open channel flows, especially in channel bends. Preliminary numerical experiments in a U-shaped and a sine-generated experimental channel indicate that the proposed method performs quite well in predicting the change of bed-deformation in channel bends due to suspended sediment transport. This method provides an effective alternative for the simulations of channel morphodynamic changes.
