MEASUREMENT AND MODELLING OF SUSPENDED SEDIMENT SIZE PROFILES ABOVE SANDY RIPPLED BEDS UNDER WAVES

2011 ◽  
Author(s):  
PETER D. THORNE ◽  
ALAN G DAVIES ◽  
RODOLFO BOLANOS
Keyword(s):  
Suspended Sediment ◽  
Sediment Size ◽  
Rippled Beds

Suspended sediment transport in rigid boundary channels at limit deposition

1998 ◽  
Vol 37 (1) ◽  
pp. 147-154 ◽  
Author(s):  
Chandramouli Nalluri ◽  
Fabio Spaliviero
Keyword(s):  
Experimental Data ◽  
Sediment Transport ◽  
Suspended Sediment ◽  
Technical Problem ◽  
Friction Model ◽  
Suspended Sediment Transport ◽  
Rigid Boundary ◽  
Sediment Size ◽  
Wide Range ◽  
The University

Sedimentation or deposition of sediments is a crucial economical and technical problem for the design of conveyances carrying sediment laden flow such as sewers, irrigation canals and, in general, rigid boundary channels. In light of investigations on sediment transport at the limit of deposition carried out during the last two decades at the University of Newcastle upon Tyne, experimental data on suspended sediment transport collected by Pulliah (1978), Macke (1982) and Arora (1983) are analysed. The data cover a wide range of volumetric concentrations (3.7 to 48542 ppm) and sediment size (0.006 to 0.37 mm). A new model for the prediction of suspended sediment transport in rigid boundary channels at limit deposit is proposed. The model was fitted by multiple regression analysis to Macke's (1982) and Arora's (1983) experimental data. Pulliah's (1978) data validate the relation. Nalluri et al. (1994) bed load friction model is checked with available data and a good agreement is observed.

scholarly journals Flood Suspended Sediment Transport: Combined Modelling from Dilute to Hyper-Concentrated Flow

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 379
Author(s):  
Jaan H. Pu ◽  
Joseph T. Wallwork ◽  
Md. Amir Khan ◽  
Manish Pandey ◽  
Hanif Pourshahbaz ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Measured Data ◽  
Suspended Sediment Transport ◽  
Good Correspondence ◽  
Local Flow ◽  
Sediment Size ◽  
Proposed Model ◽  
Wide Range ◽  
Dilute Flows

During flooding, the suspended sediment transport usually experiences a wide-range of dilute to hyper-concentrated suspended sediment transport depending on the local flow and ground conditions. This paper assesses the distribution of sediment for a variety of hyper-concentrated and dilute flows. Due to the differences between hyper-concentrated and dilute flows, a linear-power coupled model is proposed to integrate these considerations. A parameterised method combining the sediment size, Rouse number, mean concentration, and flow depth parameters has been used for modelling the sediment profile. The accuracy of the proposed model has been verified against the reported laboratory measurements and comparison with other published analytical methods. The proposed method has been shown to effectively compute the concentration profile for a wide range of suspended sediment conditions from hyper-concentrated to dilute flows. Detailed comparisons reveal that the proposed model calculates the dilute profile with good correspondence to the measured data and other modelling results from literature. For the hyper-concentrated profile, a clear division of lower (bed-load) to upper layer (suspended-load) transport can be observed in the measured data. Using the proposed model, the transitional point from this lower to upper layer transport can be calculated precisely.

scholarly journals On the Issue of Calculation of the Suspended Sediment Load Discharge

2020 ◽  
Author(s):  
Keyword(s):  
Suspended Sediment ◽  
Error Probability ◽  
Analytical Formula ◽  
Calculation Error ◽  
Flow State ◽  
Lower Error ◽  
Sediment Size ◽  
Calculated Probability ◽  
Sediment Flow ◽  
Load Discharge

The article deals with the questions of the contribution of suspended sediment in the processes of formation of the channel, and includes several formulas of suspended sediment discharge calculation and the results of calculations by these formulas. An analytical formula of sediments, in which the absolute exponent of the degree of arguments is equal to one shown the lower error probability. The calculated probability of calculation error is explicitly related to the average relative deviation between the calculated and observed values of sediment flow: the formulas with a lower error probability show better correspondence to the observed values. At the same time, the parameters of the analytical formula of sediment flow integral with respect to the type of bottom sediments represent a more stable dependence of the hydraulic variables of the flow state and sediments in contrast to the formulas of a similar purpose with data on sediment size included in them. This is explained by the fact that even quantum estimates of particle size are often unreliable and have high variability within one phase of water content, whereas the parameters focused on the qualitative state of the system (category of sediment size) characterize the properties of the bottom soil on average (integrally) over the cross-section of the flow.

scholarly journals Variability of suspended sediment grain size distribution in winter floods

2016 ◽  
Vol 48 (2) ◽  
pp. 141-151
Author(s):  
Agnieszka Hejduk ◽  
Leszek Hejduk
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Standard Deviation ◽  
Size Distribution ◽  
Suspended Sediment ◽  
Grain Size Distribution ◽  
Sediment Grain Size ◽  
Mean Values ◽  
Average Value ◽  
Sediment Size

Abstract Variability of suspended sediment grain size distribution in winter floods. The work presents the results of research concern variability of suspended sediment grain size, transported during the winter floods in agricultural catchment, in the period of hydrological years 2012-2015. The information about grain size distribution from nine winter flood events were collected over the study period, which allowed to analyze the variability of suspended sediment particle size during the various events. Grain size of sediment was determined using a laser particle size analyzer Mastersizer Microplus from Malvern Instruments Ltd. Variability of individual particle size classes were observed in each flood. Sand fraction dominated in seven of nine measured events. There was no significant increase of suspended sediment size in relation to the maximum of discharge. It can be explain by a relatively low discharge of recorded events. The percentage of material classified as clay (<4 μm) ranged from 0.08 to 1.01%, silt-sized material (>4 and <63 μm) ranged between 9.31 and 67.17% and sand-size material (>63 μm) ranged from 32.01 to 90.61%. The relationship between the particle size and the discharge requires further studies. The diameter d10, d50 and d90 and a standard deviation were calculated for each flood. Mean values of d50 for individual flood ranged between 41.05 and 191.32 μm with average value of 99.01 μm and average standard deviation of 32.57.

scholarly journals Field Measurement of Suspended Sediment Size Distribution

2011 ◽  
Vol 67 (2) ◽  
pp. I_476-I_480
Author(s):  
Yoshiaki KURIYAMA ◽  
Takayuki SUZUKI ◽  
Shin-ichi YANAGISHIMA ◽  
Ken-ichi UZAKI ◽  
Yoshio ISHINO ◽  
...  
Keyword(s):  
Size Distribution ◽  
Suspended Sediment ◽  
Field Measurement ◽  
Sediment Size

scholarly journals Simulated Flow Velocity Structure in Meandering Channels: Stratification and Inertia Effects Caused by Suspended Sediment

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1254
Author(s):  
Fei Yang ◽  
Xuejun Shao ◽  
Xudong Fu ◽  
Ehsan Kazemi
Keyword(s):  
Secondary Flow ◽  
Suspended Sediment ◽  
Velocity Structure ◽  
Boussinesq Approximation ◽  
Sediment Concentration ◽  
Hydrodynamic Equations ◽  
Inertia Effect ◽  
Meandering Channels ◽  
Sediment Size ◽  
Stratification Effect

In this study, the coupled effects of sediment inertia and stratification on the pattern of secondary currents in bend-flows are evaluated using a 3D numerical model. The sediment inertia effect, as well as the stratification effect induced by the non-uniform distribution of suspended sediment, is accounted for by adopting the hydrodynamic equations without the Boussinesq approximation. The 3D model is validated by existing laboratory experimental results. Simulation results of a simplified meandering channel indicate that sediment stratification effect enhances the intensity of secondary flow via reducing eddy viscosity, while sediment inertia effect suppresses it. The integrated effects result in an increase and a reduction in the secondary flow, respectively, at lower and higher concentrations (near-bed volumetric concentrations of 0.015 and 0.1 are, respectively, considered in this study). This suggests that the dominance of the suspended sediment effect depends on the sediment concentration profile. With the increase of concentration under a specific sediment size, the secondary flow rises to reach a maximum, and then decreases. Moreover, as the sediment concentration increases, an exponentially decaying rate has been found for the secondary flow. It is concluded that in the numerical simulation of flow in meandering channels, when concentration is high, the variable-density hydrodynamic equations without the Boussinesq approximation should be considered.

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