DS0101 -

Size Segregation in Sediment Transport – SegSed

Size Segregation in Sediment Transport

Flooding disasters, aquatic ecosystems and Earth landscapes are heavily impacted by the quantity and the quality of sediment transported by rivers within the critical zone. An important reason for our limited ability to predict sediment transport is due to the very wide range of grain sizes leading to size segregation or grain size sorting. Segregation, a major experimental and modelling scientific bottleneck largely modifies fluxes and results in patterns seen ubiquitously in nature.

A multi-scale and multi-disciplinary study of size segregation to ultimately improve sediment transport modelling.

The specific objectives of the project are to (i) experimentally improve our understanding of size segregation physical processes, especially particle-particle interactions and the feedback with the transporting fluid (ii) develop a hierarchy of process-based models at different scales for understanding, predicting and upscaling (iii) incorporate validated elementary segregation formulations in sediment transport civil and bioengineering models to ultimately improve their predictive capability.

The project is organized in 4 multidisciplinary work packages: experimental, numerical, image analysis and management and multiscale analysis, investigating at interconnected scales. WP1 is devoted to original experimental investigations. Starting from the inherent complexity of field measurements and analysis, the structure follows a downscaling path proposing 3D experiments with natural material, quasi 2D experiments with spherical glass beads and finally 2D dry granular experiments. WP2 follows an upscaling path from Euler/Lagrange models to shallow water engineering models including Euler/Euler and mixture models. Once validated on experimental results, process-based bedload transport models will also help interpret experimental findings at different scales. WP3 is entirely devoted to image analysis, especially particle tracking and segmenting algorithms. Open source sediment tracking algorithms and ground-truth datasets will be made available.

- High seasonality of sediment rates in Draix and influence of suspended solids on bedload transport measuring.
- Despite increased complexity, two-size equilibrium slopes as a function of grain size ratio and percent fine feed are similar whether with idealized glass beads or natural material.
- Supported granular flows are characterized by spatial instabilities yielding unusual segregation processes and constitutive relationships.
- the shear rate through the dimensionless inertial number is actually an important control parameter in vertical size segregation
- Developing and parallelization of the Yde-DEM code on UMS Gricad servers. Award winner at Hackaton HPC 2018 » organised by GENCI
hackathon-hpc.sciencesconf.org/resource/page/id/6.
- New Tracking particle-filter based algorithm and two ground truths included in open source package BeadTracking downloadable on github (https://github.com/hugolafaye/BeadTracking ) .

PhD Students and post-doctoral scholars have been hired. Nice perspectives are expected for each elementary tasks. As advocated by this project, original multi-scale actions should take place. Discussions are underway about (i) Eulerian two-phase modelling of stream reaches within the Draix Observatory (ii) refining of segregation-diffusion mixture models with the help of Lagrangian numerical experiments and (iii) inter-comparison of dry vs. water sheared granular flows on erodible beds

Dudill, A., Venditti, J. G., Church, M., Frey, P., 2020. Comparing the behaviour of spherical beads and natural grains in bedload mixtures Earth Surface Processes and Landforms, doi:10.1002/esp.4772.

Frey, P., Lafaye de Micheaux, H., Bel, C., Maurin, R., Rorsman, K., Martin, T., Ducottet, C., 2020. Experiments on grain size segregation in bedload transport on a steep slope. Advances in Water Resources 136, 103478, doi:10.1016/j.advwatres.2019.103478.

Dudill, A., Lafaye de Micheaux, H., Frey, P., Church, M., 2018. Introducing Finer Grains Into Bedload: The Transition to a New Equilibrium. Journal of Geophysical Research: Earth Surface 123, 2602-2619, doi:10.1029/2018JF004847.

Frank-Gilchrist, D. P., A. Penko, and J. Calantoni 2018. Investigation of sand ripple dynamics with combined particle image and tracking velocimetry, J. Atmos. Ocean. Technol., 35(10), 2019-2036, doi:10.1175/JTECH-D-18-0054.1.

Gray, J. M. N. T., 2018. Particle Segregation in Dense Granular Flows. Annual Review of Fluid Mechanics 50, 407-433, doi:10.1146/annurev-fluid-122316-045201.

Lafaye de Micheaux, H., Ducottet, C., Frey, P., 2018. Multi-model particle filter-based tracking with switching dynamical state to study bedload transport. Machine Vision and Applications 29, 735-747, doi:10.1007/s00138-018-0925-z.

Maurin, R., Chauchat, J., Frey, P., 2018. Revisiting slope influence in turbulent bedload transport: consequences for vertical flow structure and transport rate scaling. Journal of Fluid Mechanics 839, 135-156, doi:10.1017/jfm.2017.903.

Dudill A, Frey P, Church M. 2017. Infiltration of fine sediment into a coarse mobile bed: A phenomenological study. Earth Surface Processes and Landforms 42(8): 1171-1185, doi:10.1002/esp.4080.

Jantzi, H., Liebault, F., Klotz, S., 2017. Sediment residence time in alluvial storage of black marl badlands. Catena 156, 82-91, doi:10.1016/j.catena.2017.03.026.

Flooding disasters, reproduction of salmonids, and development of Earth landscapes are all heavily impacted by the quantity and the quality of sediment transported by rivers. Yet after more than a century of work we have no satisfactory theory for sediment transport. Therefore empirical sediment transport formulas often poorly compare with field measurements, by sometimes order of magnitudes. Such poor formulas are used in engineering softwares based on two-phase shallow water equations, giving therefore overall unreliable results. Hence it is difficult to assess, for example, the impact upon a stream of extreme sediment-laden floods, which is an issue for public safety, management of water resources, and environmental sustainability within the critical zone. An important reason for our limited ability to predict sediment transport, is due to the very wide range of grain sizes leading to size segregation, also named grain size sorting. This phenomenon largely modifies fluxes and results in patterns that can be seen ubiquitously in nature, such as armoring (Fig. 1).
The overall objective of this proposal is to conduct a multi-scale and multi-disciplinary study of size segregation in sediment transport to ultimately improve sediment transport modeling.
The specific objectives of the project focused on bedload transport are to (i) improve our understanding of the physical processes in size segregation, especially particle-particle interactions and the feedback with the transporting fluid; (ii) develop a hierarchy of process-based models at different scales for understanding, predicting and upscaling (iii) incorporate validated elementary segregation formulations in classical sediment transport models to ultimately improve the predictive capability of civil and bioengineering tools.
The project will be organized in 4 multidisciplinary work packages: experimental, numerical, image analysis and management and multiscale analysis, investigating at interconnected scales (Fig. 4). WP1 is devoted to original experimental investigations. Starting from the inherent complexity of field measurements and analysis, the structure follows a downscaling path proposing 3D experiments with natural material, quasi 2D experiments with spherical glass beads and finally 2D dry granular experiments. Deliverables of WP1 include high resolution spatio-temporal datasets for understanding, theorizing and validating models. WP2 follows an upscaling path from Euler/Lagrange models to shallow water engineering models including Euler/Euler and mixture models. Once validated on experimental results, process-based bedload transport models (deliverables) will also help interpret experimental findings at different scales. WP3 is entirely devoted to image analysis since most experimental measurements (including in the field) will rely on image analysis, especially particle tracking and segmenting algorithms. Deliverables include open source sediment tracking algorithms and ground-truth datasets (true trajectories). Finally WP0 will be devoted to project management but also to promoting ’the multiscale attitude’.
A good part of requested funding is devoted to two three-year PhDs and two 12-month post-docs. The consortium includes all necessary competencies to study sediment transport on a large range of scales: physical geography/fluvial geomorphology (Irstea, UBC, SFU), civil engineering (Irstea, 3SR), granular physics (IPR), fluid (Legi, Irstea, NRL) and soil mechanics (3SR), image analysis (laHC) and applied mathematics (UM). The coordination by Irstea, an organization which has a long experience of disseminating multidisciplinary research, of research networking and transfer to public and private end-users, guarantees that this project, potentially transformative, will be much more than the juxtaposition of isolated research.

Project coordinator

Monsieur Philippe Frey (Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture - UR erosion torrentielle, neige et avalanches)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

UM School of Mathematics, University of Manchester
UBC University of British Columbia - Dept of Geography
SFU Simon Fraser University - Dept of Geography
NRL-SSC Marine Geosciences Division, Naval Research Laboratory
IPR Institut de Physique de Rennes, Université Rennes 1
grenoble INP / 3SR Institut polytechnique de Grenoble,Laboratoire Sols, Solides, Structures, Risques,
Irstea - Etna Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture - UR erosion torrentielle, neige et avalanches
IPR Institut de Physique de Rennes, Université Rennes 1
LEGI-CNRS Laboratoire ecoulements geophysiques et indsutriels
UJM/LaHC Laboratoire Hubert Curien

Help of the ANR 569,323 euros
Beginning and duration of the scientific project: November 2016 - 48 Months

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