Experimental Study on the Characteristics of Sediment Transport and Sorting in Pressurized Pipes

Sediment transport in pipes is an effective engineering measure used to reallocate water–sediment resources and is widely used in reservoir flooding and sediment discharging, river dredging, floodplain area deposition, as well as other projects. An experimental investigation of sediment transport in pressurized pipes, with heterogeneous sediment (d50 = 107 μm) of the lower Yellow River as the experimental material, is presented. This study mainly explored the change law of sediment transport and sorting in pressure pipes with an internal diameter of 0.08 m. The experimental results reveal that the presence of sediment significantly changed the distribution of the flow velocity field. At the same flow rate, the velocity of the lower water body with a high sediment concentration decreased, while that of the upper water body increased. At a low water flow rate, the increase in sediment concentration caused an asymmetric distribution of the cross-sectional velocity. The vertical concentration decreased in height, and the obvious stratification of vertical sediment particles was observed. With the increase in the flow rate, the asymmetry of the velocity distribution significantly decreased, the concentration profile tended towards being uniformly distributed along the vertical direction, and the separation effect of the sediment particles weakened.

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Emergent stationarity in Yellow River sediment transport and the underlying shift of dominance: from streamflow to vegetation

Hydrology and Earth System Sciences ◽

10.5194/hess-23-549-2019 ◽

2019 ◽

Vol 23 (1) ◽

pp. 549-556 ◽

Cited By ~ 4

Author(s):

Sheng Ye ◽

Qihua Ran ◽

Xudong Fu ◽

Chunhong Hu ◽

Guangqian Wang ◽

...

Keyword(s):

Sediment Transport ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Yellow River ◽

Yellow River Basin ◽

Sediment Concentration ◽

Topographic Characteristics ◽

The Yellow River Basin ◽

Annual Scale ◽

Annual Discharge

Abstract. Soil erosion and sediment transport play important roles in terrestrial landscape evolution and biogeochemical cycles of nutrients and contaminants. Although discharge is considered to be a controlling factor in sediment transport, its correlation with sediment concentration varies across the Yellow River basin (YRB) and is not fully understood. This paper provides analysis from gauges across the YRB covering a range of climates, topographic characteristics, and degrees of human intervention. Our results show that discharge control on sediment transport is dampened at gauges with large mean annual discharge, where sediment concentration becomes more and more stable. This emergent stationarity can be attributed to vegetation resistance. Our analysis shows that sediment concentration follows a bell shape with vegetation index (normalized difference vegetation index, NDVI) at an annual scale despite heterogeneity in climate and landscape. We obtain the counterintuitive result that, as mean annual discharge increases, the dominant control on sediment transport shifts from streamflow erosion to vegetation retardation in the YRB.

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Experimental study of sediment transport processes and size selectivity of eroded sediment on steep Pisha sandstone slopes

10.5194/egusphere-egu2020-2269 ◽

2020 ◽

Author(s):

Pan Zhang ◽

Pingqing Xiao ◽

Chunxia Yang

Keyword(s):

Sediment Transport ◽

Flow Velocity ◽

Overland Flow ◽

Yellow River ◽

Transport Processes ◽

The Yellow River ◽

Size Selectivity ◽

Coarse Sediment ◽

Sediment Particles ◽

Slope Flow

The Pisha sandstone area on the Ordos Plateau of China is the primary source of coarse sediment of the Yellow River. Sediment size distribution and selectivity greatly affect sediment transport and deposition. Hence, sediment transport processes and size selectivity by overland flow on Pisha sandstone slopes were investigated in this study. Experiments were run with Pisha sandstone soil (bulk density of 1.35 g/cm3) under rainfall intensities of 87 and 133 mm/h with a 25&#176; slope gradient, and the duration of simulated rainfall is 1 h. Sediment and runoff were sampled at 2-min intervals to examine the size distribution change of the eroded sediment. The particle composition, enrichment rate, fractal dimension, and time distribution characteristics of median grain size (d50) of eroded sediment were comprehensively analyzed. Statistical analyses showed that the erosion process of Pisha sandstone slope mainly transported coarse sediment. More than 40% of eroded sediment particles were coarse sediment, which will become the main sediment in the lower reaches of the Yellow River bed. The particle size of eroded sediment tended to gradually decrease with the continuous rainfall but remained larger than the background value of Pisha sandstone soil after refinement. The fractal dimension was positively correlated with the slope flow velocity, while the d50 was negatively correlated with the slope flow velocity. Overall, these findings show a strong relationship between the sediment transport and flow velocity, which indicates that the selectivity and transportation of sediment particles on the Pisha sand slopes is mainly influenced by the hydrodynamic parameters of overland flow. This study provides a methodology and data references for studying the particle selectivity characteristics of eroded sediment and provides a scientific basis for revealing the mechanism of erosion and sediment yield in the Pisha sandstone area of China.

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MODELING SEDIMENT TRANSPORT IN THE YELLOW RIVER MOUTH

Coastal Engineering Proceedings ◽

10.9753/icce.v32.posters.13 ◽

2011 ◽

Vol 1 (32) ◽

pp. 13

Author(s):

Haibo Zong ◽

Pingxing Ding ◽

Fengyan Shi

Keyword(s):

Sediment Transport ◽

Yellow River ◽

Sediment Resuspension ◽

River Mouth ◽

Sediment Concentration ◽

The Yellow River ◽

Numerical Studies ◽

Wave Effects ◽

Coastal Sediment Transport ◽

Yellow River Mouth

Yellow River is famous for its high sediment concentration, which carries a huge amount of sediment into Bohai Sea during the flood season. In the mouth of Yellow River, the suspended sediment concentration (here after: SSC) are relatively high and the average depth is generally shallow. Recent studies indicated that in the shallow and micro-tide area, wave usually is a primary mechanism for bottom sediment resuspension. Most numerical studies of sediment transport in the Yellow River mouth didn't include the wave effects. To analyze the sediment transport in the Yellow River mouth with wave effect, a Coastal Sediment Transport Modeling System (CSTMS) was applied in this study.

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Suspended sediment concentration and deformation of riverbed in a frazil jammed reach

Canadian Journal of Civil Engineering ◽

10.1139/l00-038 ◽

2000 ◽

Vol 27 (6) ◽

pp. 1120-1129 ◽

Cited By ~ 23

Author(s):

Jueyi Sui ◽

Desheng Wang ◽

Bryan W Karney

Keyword(s):

Sediment Transport ◽

Open Channel ◽

Field Experiments ◽

Suspended Sediment Concentration ◽

Yellow River ◽

Sediment Concentration ◽

Ice Jams ◽

Frazil Ice ◽

Ice Jam ◽

Load Sediment

The presence of ice in rivers affects hydrodynamic conditions through changes in both the river's boundary conditions and its thermal regime. Therefore, the characteristics of sediment transport and the deformation of the river channel in ice-covered rivers are quite different from those experiencing conventional open channel flow. The variables of ice behavior, ice jamming extent, sediment transport, and deformation of the riverbed during ice periods are interrelated on the basis of both physical arguments and field experiments of river ice jams in the Hequ Reach of the Yellow River. The characteristics of sediment concentration in water, frazil ice, and ice cover are described. Analyses have been made on the mechanism of the evolution of frazil jam and the associated adjustments in the riverbed. It has been found that the evolution of the ice jam and the deformation of the riverbed reinforce each other. The interrelationship between the particular features of evolution of ice jam and deformation of riverbed is summarized here in the form of regression relationships relating the hydraulic parameters of water under ice jams to the deformation-extent of the riverbed and the jamming-extent.Key words: deformation of riverbed, evolution of frazil jam, frazil jam, suspended load, sediment concentration.

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Study on Dynamic Equilibrium of Sediment Transport by Qingshuigou Course of the Yellow River

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.212-213.351 ◽

2012 ◽

Vol 212-213 ◽

pp. 351-357 ◽

Cited By ~ 1

Author(s):

Shou Bing Yu ◽

Kai Rong Wang ◽

Wan Zhan Wang

Keyword(s):

Sediment Transport ◽

Dynamic Equilibrium ◽

Yellow River ◽

River Estuary ◽

Longitudinal Section ◽

Sediment Concentration ◽

Yellow River Estuary ◽

Water Volume ◽

The Yellow River ◽

Annual Total

The multi-object application of the Xiaolangdi Reservoir and water and sediment regulation have greatly changed flow and sediment conditions emptying into the Yellow River Estuary. By use of flow and sediment field data at the Lijin Hydrological Station and river cross-section elevation data during 2001~2010, the paper has analyzed characteristics of the Yellow River Estuary in terms of incoming flow and sediment conditions, main flume area, average river longitudinal section and river length. The results show that annual total water volume emptying into the Estuary since 2003 has maintained about 200×108 m3, annual total sediment 1.77×108 t, whole annual average sediment concentration 9.3kg/m3, which are stable and beneficial for dynamic equilibrium of sediment transport. Interannual stability of main flume area, average river bed elevation and river length since the Lijin Section during 2007-2010 indicate that current Qingshuigou Course of the Yellow River has achieved dynamic equilibrium of sediment transport.

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Emergent stationarity in Yellow River sediment transport and the underlying shift of dominance: from streamflow to vegetation

10.5194/hess-2018-265 ◽

2018 ◽

Author(s):

Sheng Ye ◽

Qihua Ran ◽

Xudong Fu ◽

Chunhong Hu ◽

Guangqian Wang ◽

...

Keyword(s):

Sediment Transport ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Yellow River ◽

Yellow River Basin ◽

Sediment Concentration ◽

Topographic Characteristics ◽

The Yellow River Basin ◽

Annual Scale ◽

Annual Discharge

Abstract. Soil erosion and sediment transport play important roles in terrestrial landscape evolution and biogeochemical cycles of nutrients and contaminants. Although discharge is considered to be a controlling factor in sediment transport, its correlation with sediment concentration varies across the Yellow River Basin (YRB) and is not fully understood. This paper provides analysis from gauges across the YRB covering a range of climate, topographic characteristics and degree of human intervention. Our results show that discharge control on sediment transport is dampened at gauges with large mean annual discharge, where sediment concentration becomes more and more stable. This emergent stationarity can be attributed to vegetation resistance. Our analysis shows that sediment concentration follows a bell shape with vegetation index (normalized difference vegetation index, NDVI) at annual scale despite heterogeneity in climate and landscape. We obtain the counterintuitive result that as mean annual discharge increases, the dominant control on sediment transport shifts from streamflow erosion to vegetation retardation in the YRB.

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Effect of Water Flow on Underwater Wet Welded A36 Steel

Metals ◽

10.3390/met11050682 ◽

2021 ◽

Vol 11 (5) ◽

pp. 682

Author(s):

Eko Surojo ◽

Aziz Harya Gumilang ◽

Triyono Triyono ◽

Aditya Rio Prabowo ◽

Eko Prasetya Budiana ◽

...

Keyword(s):

Mechanical Properties ◽

Water Flow ◽

Flow Rate ◽

Water Flow Rate ◽

Physical And Mechanical Properties ◽

Shielded Metal Arc Welding ◽

Effect Of Water ◽

Bending Effect ◽

Metal Arc Welding ◽

A36 Steel

Underwater wet welding (UWW) combined with the shielded metal arc welding (SMAW) method has proven to be an effective way of permanently joining metals that can be performed in water. This research was conducted to determine the effect of water flow rate on the physical and mechanical properties (tensile, hardness, toughness, and bending effect) of underwater welded bead on A36 steel plate. The control variables used were a welding speed of 4 mm/s, a current of 120 A, electrode E7018 with a diameter of 4 mm, and freshwater. The results show that variations in water flow affected defects, microstructure, and mechanical properties of underwater welds. These defects include spatter, porosity, and undercut, which occur in all underwater welding results. The presence of flow and an increased flow rate causes differences in the microstructure, increased porosity on the weld metal, and undercut on the UWW specimen. An increase in water flow rate causes the acicular ferrite microstructure to appear greater, and the heat-affected zone (HAZ) will form finer grains. The best mechanical properties are achieved by welding with the highest flow rate, with a tensile strength of 534.1 MPa, 3.6% elongation, a Vickers microhardness in the HAZ area of 424 HV, and an impact strength of 1.47 J/mm2.

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Design and thermal characteristic analysis of motorized spindle cooling system

Advances in Mechanical Engineering ◽

10.1177/16878140211020878 ◽

2021 ◽

Vol 13 (5) ◽

pp. 168781402110208

Author(s):

Yuan Zhang ◽

Lifeng Wang ◽

Yaodong Zhang ◽

Yongde Zhang

Keyword(s):

Flow Rate ◽

High Speed ◽

Thermal Deformation ◽

Cooling System ◽

Thermal Characteristic ◽

Water Flow Rate ◽

Thermal Characteristics ◽

Characteristic Analysis ◽

Motorized Spindle ◽

Experiment And Simulation

The thermal deformation of high-speed motorized spindle will affect its reliability, so fully considering its thermal characteristics is the premise of optimal design. In order to study the thermal characteristics of high-speed motorized spindles, a coupled model of thermal-flow-structure was established. Through experiment and simulation, the thermal characteristics of spiral cooling motorized spindle are studied, and the U-shaped cooled motorized spindle is designed and optimized. The simulation results show that when the diameter of the cooling channel is 7 mm, the temperature of the spiral cooling system is lower than that of the U-shaped cooling system, but the radial thermal deformation is greater than that of the U-shaped cooling system. As the increase of the channel diameter of U-shaped cooling system, the temperature and radial thermal deformation decrease. When the diameter is 10 mm, the temperature and radial thermal deformation are lower than the spiral cooling system. And as the flow rate increases, the temperature and radial thermal deformation gradually decrease, which provides a basis for a reasonable choice of water flow rate. The maximum error between experiment and simulation is 2°C, and the error is small, which verifies the accuracy and lays the foundation for future research.

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Experimental Characterization of a Modified Airlift Pump

Volume 7: Fluids Engineering Systems and Technologies ◽

10.1115/imece2014-39899 ◽

2014 ◽

Author(s):

Afshin Goharzadeh ◽

Keegan Fernandes

Keyword(s):

Water Flow ◽

Flow Rate ◽

High Speed ◽

Water Flow Rate ◽

High Speed Photography ◽

Two Phase ◽

Inner Diameter ◽

Airlift Pump ◽

Flow Map ◽

Churn Flow

This paper presents an experimental investigation on a modified airlift pump. Experiments were undertaken as a function of air-water flow rate for two submergence ratios (ε=0.58 and 0.74), and two different riser geometries (i) straight pipe with a constant inner diameter of 19 mm and (ii) enlarged pipe with a sudden expanded diameter of 19 to 32 mm. These transparent vertical pipes, of 1 m length, were submerged in a transparent rectangular tank (0.45×0.45×1.1 m3). The compressed air was injected into the vertical pipe to lift the water from the reservoir. The flow map regime is established for both configurations and compared with previous studies. The two phase air-water flow structure at the expansion region is experimentally characterized. Pipeline geometry is found to have a significant influence on the output water flow rate. Using high speed photography and electrical conductivity probes, new flow regimes, such as “slug to churn” and “annular to churn” flow, are observed and their influence on the output water flow rate and efficiency are discussed. These experimental results provide fundamental insights into the physics of modified airlift pump.

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