Theoretical Investigation into Plunging Point of Density Current in Reservoir

2012 ◽  
Vol 212-213 ◽  
pp. 413-416
Author(s):  
Tao Li ◽  
Guo Ming Gao ◽  
Huai Bao Ma ◽  
Ting Wang
Keyword(s):  
Froude Number ◽  
Taylor Series ◽  
Yellow River ◽  
Sediment Concentration ◽  
Density Current ◽  
Correction Coefficient ◽  
Water And Sediment ◽  
Current Design ◽  
Xiaolangdi Reservoir ◽  
Water And Sediment Regulation

The study of the beginning of the density current is the first formation of density current. The relation formula for gravitational correction coefficient had been derived on Taylor series. Then the explicit changing formula between Froude number and sediment concentration had been obtained. Analysis and discussion about the formula had been carried out. With the data surveyed from Xiaolangdi Reservoir had been validated on the coefficient. The results show that the formula can support Xiaolangdi reservoir for the density current design of water and sediment regulation on Yellow River.

scholarly journals Variation on sandbar of tributary in Xiaolangdi Reservoir on Yellow River, China

2018 ◽  
Vol 246 ◽  
pp. 01019
Author(s):  
Tao Li ◽  
Jun-hua Zhang ◽  
Guoming Gao ◽  
Huaibao Ma
Keyword(s):  
Flood Control ◽  
Yellow River ◽  
Deposition Process ◽  
Utilization Efficiency ◽  
Comprehensive Utilization ◽  
Water And Sediment ◽  
River Bed ◽  
Main River ◽  
Effective Use ◽  
Xiaolangdi Reservoir

Sandbar development would stop the water and sediment exchange between main river and tributary and even influence the normal reservoir opeartion. From the surveyed data of reservoir built many years ago, it shows that when there is a bar in tributary mouth, the tributary volume below the bar will become nullification during the period of flood control or water and sediment regulation of reservoir. There are more tributaries in Xiaolangdi reservoir than the others that it occupies 41.3% of the total initial volume of tributary volume. Obviously, the effective use of tributary volume has been important influenced by comprehensive utilization efficiency of reservoir scheduling, such as flood control, sedimentation reduction and comprehensive utilization. Results of Xiaolangdi Reservoir mobile-bed physical model experiments show that tributary is equivalent to lateral extension of river bed, the tributary intrusion deposition process have strongly relations with the factors, such as original topography, river bed deposition shape and its regime, process with input discharge and input sediment, and method of reservoir regulation. The variation trends of main river and tributary terrain forecasted by model test are basically in accordance with field surveyed data. The results could be used for research, design, and forecasting of reservoirs in sediment-laden river.

scholarly journals Study on the evolution law of density current in the Xiaolangdi Reservoir before the flood in 2018

2018 ◽  
Vol 246 ◽  
pp. 01050
Author(s):  
Xinjie Li ◽  
Yuanjian Wang ◽  
Shaojun Qu ◽  
Ting Wang ◽  
Kunpeng Li
Keyword(s):  
Flow Velocity ◽  
Water Level ◽  
Yellow River ◽  
The Yellow River ◽  
Density Current ◽  
Sediment Characteristics ◽  
Sediment Thickness ◽  
Evolution Law ◽  
Research Results ◽  
Xiaolangdi Reservoir

Sediment problems affect the operation life and comprehensive benefits of a reservoir. In response to the floods in the middle and upper reaches of the Yellow River, the Xiaolangdi Reservoir is subjected to preventative pre-discharge scheduling. Through a prototypical observation of the density current plunging zone of the Xiaolangdi Reservoir in 2018, we collected prototypical data of the water level, water-sediment characteristics, sediment thickness, thalweg points, and flow velocity, and analyzed the pre-dam distribution of density current and scouring-sedimentation characteristics during the flood dispatching period of the Xiaolangdi Reservoir. The research results promoted the understanding of the movement law of the density current of the Xiaolangdi Reservoir and the development of efficient sediment drainage technology for reservoirs.

scholarly journals Response of Erosion and Deposition of Channel Bed, Banks and Floodplains to Water and Sediment Changes in the Lower Yellow River, China

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 357 ◽  
Author(s):  
Xiaofei Liu ◽  
Changxing Shi ◽  
Yuanyuan Zhou ◽  
Zhenkui Gu ◽  
Huijuan Li
Keyword(s):  
Yellow River ◽  
Water Discharge ◽  
Sediment Concentration ◽  
Main Channel ◽  
River Channel ◽  
Lower Yellow River ◽  
Main Research ◽  
The Lower Yellow River ◽  
Water And Sediment ◽  
Geomorphic Units

River channel change can be very sensitive to environmental change and human activities and it has been one of the main research topics in fluvial geomorphology. In this study, repeated channel geometric measurements were used to investigate the channel adjustment to water and sediment changes of the lower Yellow River in China in the past few decades. With a high sediment concentration and large variations of water discharge, the lower Yellow River has a much active channel in its form and location, which has hindered previous research efforts to study long-term differentiated erosion/deposition of different geomorphic units in the channel. In this study, we divided each of four typical channel across-sections at hydrological stations in the lower Yellow River into different units according to the geomorphological features, and give a detailed investigation of erosion/deposition processes of these geomorphic units and the interactions between them besides the influence of incoming water and sediment conditions. The results show that with a significant decreasing trend of both the annual runoff and sediment load of the river and abrupt changes in 1985–1996, the overall siltation trend in the river channel before 1990 had been replaced by a slight erosion trend after 2006. In the earlier period, the siltation in the upstream wandering and transitional reaches mainly occurred on floodplains and that in the downstream straight reaches principally on main channel bed. In the later period, erosion occurred mainly on high and low bank slopes in the wandering reaches and on main channel bed in the transitional reaches. The erosion became weak in the wandering reaches after 2010, continued in the transitional reaches, and was still relatively minor in the straight reaches, reflecting the downstream hysteresis channel response to changes in water and sediment discharges down dams. Our results suggest that the seasonal erosion/deposition of a geomorphic unit of the river channel can be attributed to the changes in water and sediment discharges as well as to the interaction between geomorphic units. Siltation on the main channel bed could be attributed to erosion on the bank slopes in both the sections in the wandering and transitional reaches, and erosion of the main channel bed in flood seasons was negatively related with the mean water discharge at the two sections in the straight reaches. This result implies that fixing the bank slopes in the wandering and transitional reaches and raising the water discharge in the straight reach in flood seasons are favorable options for controlling the development of the two-level perching channel of the lower Yellow River.

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