Sediment Transport: New Approach and Analysis

doi:10.1061/JYCEAJ.0003791

Journal Article•DOI•

Sediment Transport: New Approach and Analysis

01 Nov 1973-Journal of Hydraulic Engineering (ASCE)-Vol. 99, Iss: 11, pp 2041-2060

TL;DR: In this article, the relationship of sediment transport to fluid flow is considered and predictive equations are derived which relate total sediment flux to measurable properties of flow, and a preliminary comparison is made with observations from other sources, including natural rivers.

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Abstract: The relationship of sediment transport to fluid flow is considered. Physical reasoning leads to dimensionless groupings of the variables which are different for coarse sediment and for fine sediment, because of dissimilar modes of transport. This concept provides a basis for a new analysis of data from flume experiments, and a method for dealing with transitional sizes of sediment is suggested. The analysis of experimental data supports the theory put forward and predictive equations are derived which relate total sediment flux to measurable properties of flow. A preliminary comparison is made with observations from other sources, including natural rivers.

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Journal Article•DOI•

Sediment transport; Part I, Bed load transport

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van Rijn, C Leo

01 Oct 1984-Journal of Hydraulic Engineering

TL;DR: In this article, a method is presented which enables the computation of the bed-load transport as the product of the saltation height, the particle velocity and the bed load concentration.

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Abstract: A method is presented which enables the computation of the bed-load transport as the product of the saltation height, the particle velocity and the bed-load concentration. The equations of motions for a solitary particle are solved numerically to determine the saltation height and particle velocity. Experiments with gravel particles (transported as bed load) are selected to calibrate the mathematical model using the lift coefficient as a free parameter. The model is used to compute the saltation heights and lengths for a range of flow conditions. The computational results are used to determine simple relationships for the saltation characteristics. Measured transport rates of the bed load are used to compute the sediment concentration in the bed-load layer. A simple expression specifying the bed-load concentration as a function of the flow and sediment conditions is proposed. A verification analysis using about 600 (alternative) data shows that about 77% of the predicted bed-load-transport rates are within 0.5 and 2 times the observed values.

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1,653 citations

Cites background or methods from "Sediment Transport: New Approach an..."

...For comparison the formulas of EngelundHansen (12) and Ackers-White (2) were also applied....
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...Saltation length K/D Saltation height Measured (2)...
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...Other disadvantages of the use of the energy gradient may be: (1) The variations due to nonequilibrium phenomena (rising and falling stages); and (2) measuring problems in (isolated) field conditions....
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...Usually, three modes of particle motion are distinguished: (1) Rolling and sliding motion or both; (2) saltation motion; and (3) suspended particle motion....
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...transport stage parameter, T = -^— (2) ("*,cr) in which u* = (g/C) u = bed-shear velocity related to grains, C = Chezy-coefficient related to grains, u = mean flow velocity, M#iCr = critical bed-shear velocity according to Shields (38) as given in analytical (by the writer) and graphical form in Fig....
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Journal Article•DOI•

Sediment Transport, Part II: Suspended Load Transport

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Leo C. van Rijn

01 Nov 1984-Journal of Hydraulic Engineering

TL;DR: In this article, a method is presented which enables the computation of the suspended load as the depth-integration of the product of the local concentration and flow velocity, based on the calculation of the reference concentration from the bed-load transport.

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Abstract: A method is presented which enables the computation of the suspended load as the depth-integration of the product of the local concentration and flow velocity. The method is based on the computation of the reference concentration from the bed-load transport. Measured concentration profiles have been used for calibration. New relationships are proposed to represent the size gradation of the bed material and the damping of the turbulence by the sediment particles. A verification analysis using about 800 data shows that about 76% of the predicted values are within 0.5 and 2 times the measured values.

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1,564 citations

Journal Article•DOI•

A systematic analysis of eight decades of incipient motion studies, with special reference to gravel-bedded rivers

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John M. Buffington, David R. Montgomery

01 Aug 1997-Water Resources Research

TL;DR: In this article, the authors used data compiled from eight decades of incipient motion studies to calculate dimensionless critical shear stress values of the median grain size, t* c 50.

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Abstract: Data compiled from eight decades of incipient motion studies were used to calculate dimensionless critical shear stress values of the median grain size, t* c 50 . Calculated t* c 50 values were stratified by initial motion definition, median grain size type (surface, subsurface, or laboratory mixture), relative roughness, and flow regime. A traditional Shields plot constructed from data that represent initial motion of the bed surface material reveals systematic methodological biases of incipient motion definition; t* c 50 values determined from reference bed load transport rates and from visual observation of grain motion define subparallel Shields curves, with the latter generally underlying the former; values derived from competence functions define a separate but poorly developed field, while theoretical values predict a wide range of generally higher stresses that likely represent instantaneous, rather than time-averaged, critical shear stresses. The available data indicate that for high critical boundary Reynolds numbers and low relative roughnesses typical of gravel-bedded rivers, reference-based and visually based studies have t* c50 ranges of 0.052-0.086 and 0.030-0.073, respectively. The apparent lack of a universal t*50 for gravel-bedded rivers warrants great care in choosing defendable t* c50 values for particular applications.

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919 citations

Cites methods from "Sediment Transport: New Approach an..."

...Despite this potential for variation, Wilcock [1988] found that reference-based r;, 0 values determined from the Parker and Klingeman [1982] and Ackers and White [1973] methods differed by only 5% for the same data set. Scatter within the reference- and competence-based data may also reflect choice of curve fitting technique [Diplas, 1987; Ashworth and Ferguson, 1989; Ashworth et al., 1992; Wathen et al., 1995]. In an extreme example, Paintal [1971, Figure 8] demonstrates that nonlinear relationships between bed load transport rate and dimensionless shear stress that are mistakenly fit with a linear function can cause up to a five-fold overestimation of reference-based T;50 values. In many cases it is difficult to assess or correct differences in curve-fitting technique between investigations due to incomplete documentation of measurements and analysis procedure. The results of Shields [1936], in particular, are often used as the standard for comparison, yet Shields' [1936] basic measurements and curve fitting technique are unreported, making it difficult to fully assess the causes of discrepancy between Shields' [1936] data...
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...Despite this potential for variation, Wilcock [1988] found that reference-based r;, 0 values determined from the Parker and Klingeman [1982] and Ackers and White [1973] methods differed by only 5% for the same data set....
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Journal Article•DOI•

Sediment Transport, Part III: Bed Forms and Alluvial Roughness

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van Rijn, C Leo

01 Dec 1984-Journal of Hydraulic Engineering

TL;DR: In this paper, a verification analysis using about 1,500 (alternative) reliable flume and field data shows good results in predicting the hydraulic roughness (friction factor).

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Abstract: A method is presented that makes the classification of bed forms, the prediction of the bed‐form dimensions and the effective hydraulic roughness of the bed forms feasible. The proposed relationships are based on the analysis of reliable flume and field data. A verification analysis using about 1,500 (alternative) reliable flume and field data shows good results in predicting the hydraulic roughness (friction factor). For field conditions, the proposed method yields considerably better results than previously proposed methods, which are reviewed here. The proposed method has also been used to predict the flow depth and the total bed‐material load.

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661 citations

Journal Article•DOI•

Turbulent open-channel flows with variable depth across the channel

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Koji Shiono¹, Donald W. Knight²•Institutions (2)

University of Bradford¹, University of Birmingham²

01 Jan 1991-Journal of Fluid Mechanics

TL;DR: In this paper, the lateral distributions of depth-mean velocity and boundary shear stress for straight open channels with prismatic complex cross-sections are derived theoretically for channels of any shape, provided that the boundary geometry can be discretized into linear elements.

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Abstract: The flow of water in straight open channels with prismatic complex cross-sections is considered. Lateral distributions of depth-mean velocity and boundary shear stress are derived theoretically for channels of any shape, provided that the boundary geometry can be discretized into linear elements. The analytical model includes the effects of bed-generated turbulence, lateral shear turbulence and secondary flows. Experimental data from the Science and Engineering Research Council (SERC) Flood Channel Facility are used to illustrate the relative importance of these three effects on internal shear stresses. New experimental evidence concerning the spatial distribution of Reynolds stresses τyx and τzx is presented for the particular case of compound or two-stage channels. In such channels the vertical distributions of τzx are shown to be highly nonlinear in the regions of strongest lateral shear and the depth-averaged values of τyx are shown to be significantly different from the depth mean apparent shear stresses. The importance of secondary flows in the lateral shear layer region is therefore established. The influence of both Reynolds stresses and secondary flows on eddy viscosity values is quantified. A numerical study is undertaken of the lateral distributions of local friction factor and dimensionless eddy viscosity. The results of this study are then used in the analytical model to reproduce lateral distributions of depth-mean velocity and boundary shear stress in a two stage channel. The work will be of interest to engineers engaged in flood channel hydraulics and overbank flow in particular.

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591 citations

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Sediment Transport: New Approach and Analysis

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