Publications associées à Grosseur de grains

Clogging of riverbed substrates by fine sediment

Riverbeds represent the habitat of numerous aquatic species. Exchanges between the groundwater, the hyporheic zone and the surface flow are also essential for river ecosystems. Fine sediment transported by rivers deposits inside or on top of the bed and mo ...

EPFL2023

Reduction of riverbed clogging related to sediment flushing

Giovanni De Cesare, Romain Maxime Dubuis

The ecological effects of dams on sediment and river flow have been subject to an increasing attention, leading to the implementation of mitigation measures such as environmental flow release and sediment replenishment. However, fine sediment dynamics have ...

CRC Press/Balkema2023

GALET: A deep learning image segmentation model for drone-based grain size analysis of gravel bars

Giovanni De Cesare, Christian Mörtl

In this study, we present the deep learning image segmentation model for drone-based grain size analysis of gravel bars called GALET. The objectives are to quantify the performance of the code and to test its applicability in river research and management. ...

International Association for Hydro-Environment Engineering and Research (IAHR)2022

Particle-size segregation and rheology coupling in dense granular flows

Tomás Alfredo Trewhela Palacios

Dense granular flows -debris or pyroclastic flows, avalanches, granular flows in heaps, silos or rotating drums-are ubiquitous to many natural and industrial processes. Their grain composition is often polydisperse, with particles differing in shape, size ...

EPFL2021

Size-resolved aerosol pH over Europe during summer

Athanasios Nenes, Spyros Pandis

The dependence of aerosol acidity on particle size, location, and altitude over Europe during a summertime period is investigated using the hybrid version of aerosol dynamics in the chemical transport model PMCAMx. The pH changes more with particle size in ...

Copernicus GmbH2021

Statistical and physical characterization of rainfall-driven overland flow morphologies

Mohsen Cheraghi

Environmental transport processes are highly coupled with the shape of landscapes. Modern catchment analysis with high-resolution data and huge computational powers demand more detailed within-cell metrics for surface evolution modeling. This dissertation ...

EPFL2019

Hydraulic-morphological habitat assessment in rivers considering residual flow, sediment replenishment and artificial flood events

Severin Stähly

Dams store water and trap sediment in their reservoirs. Downstream river segments, hence, are affected by a limited sediment dynamics. This becomes obvious by river bed incision, limited geomorphological variability and depletion of hydraulic habitats for ...

EPFL2019

Floating modular unit for controlled sediment flushing regarding sediment size and concentration

Giovanni De Cesare

Sediment management is a challenging discipline, especially in regions where the storage capacity of reservoirs decreases due to sediment accumulation. This paper shows an innovative and holistic modular technical approach to the problem, considering a gre ...

ed. Hydropower&Dams, Aqua Media International2018

The origin of fine sediment determines the observations of suspended sediment fluxes under unsteady flow conditions

Mário Jorge Rodrigues Pereira Da Franca, Carmelo Juez Jiménez

Field observations in a wide range of environments have shown that sediment availability is a major control on the suspended sediment observations in streams. Here we examine, via laboratory experiments, how the amount of proximal in-channel fine sediment ...

American Geophysical Union2018

Design optimization of permeable sediment traps for fluvial bed load transport

Anton Schleiss, Sebastian Schwindt, Mona Jafarnejad Chaghooshi, Anita Hélène Roth

Sediment traps are crucial elements for flood protection in mountain rivers with high sediment transport capacity. Existing structures often interrupt the channel connectivity. Ideally, a sediment trap should be permeable for bed load during non-hazardous ...

2018

Entrainment, transport and deposition of sediment by saline gravity currents

Anton Schleiss, Mário Jorge Rodrigues Pereira Da Franca, Carmelo Juez Jiménez, Jessica Zordan

Few studies have addressed simultaneously the feedback between the hydrodynamics of a gravity cur- rent and the geomorphological changes of a mobile bed. Hydrodynamic quantities such as turbulent and mean velocities, bed shear stress and turbulent stresses ...

2018

Erosion mechanisms during abrasive waterjet machining: Model microstructures and single particle experiments

Stefano Mischler, Johann Michler

The erosion mechanisms during abrasive waterjet (AWJ) machining have been examined for a variety of materials. However, no systematic study has considered the effect of the microstructure property relationship on the erosion mechanisms in metals. In this w ...

Elsevier Science Sa2017

LABORATORY EXPERIMENTS OF PULSED SUBAQEOUS SEDIMENT DENSITY FLOWS: INTERNAL STRATIFICATION AND LAYERING

Mário Jorge Rodrigues Pereira Da Franca, Carmelo Juez Jiménez, Mariangela Sfouni-Grigoriadou

This paper reports on an experimental study which focuses on reproducing small scale sediment density flows in a laboratory flume. The observations are aimed at improving the parametrization of the relations that govern the transition between different pha ...

2017

Analysis of mechanical-hydraulic bedload deposition control measures

Anton Schleiss, Giovanni De Cesare, Mário Jorge Rodrigues Pereira Da Franca, Sebastian Schwindt

During floods, the bedload transport of steep headwaters can exceed the hydraulic transport capacity of milder downstream reaches where settlements are often situated. Therefore, sediment retention barriers are typically installed upstream of such sensible ...

Elsevier2017

Sediment Pulses in a Gravel-Bed Flume with Alternate Bars

Blaise Etienne Marceau Dhont

The proper understanding of gravel-bed river dynamics is a crucial issue for the effective protection against related natural hazards, design of hydraulic structures, and preservation of their high ecological value in mountain regions. However, despite mor ...

EPFL2017

Linear scaling of precipitation-driven soil erosion in laboratory flumes

David Andrew Barry, Seifeddine Jomaa

The proportionality between raindrop-driven soil erosion delivery and area of soil exposed to raindrops under a uniform precipitation rate was investigated in terms of individual size classes using laboratory flume experiments. In particular, we examined t ...

Elsevier Science Bv2017

Computational hydraulic modelling of fine sediment stirring and evacuation through the power waterways at the Trift reservoir

Anton Schleiss, Pedro Filipe De Almeida Manso, Azin Amini, Célestin Leupi, Sara Venuleo

Taking advantage of the withdrawal of some glaciers, several new dams will eventually be constructed in Switzerland in the coming years as a part of the 2050 energy strategy. The Trift dam, located in Berner Oberlands in Switzerland, is one of these new pr ...

2017

Hydro-morphological processes through permeable sediment traps at mountain rivers

Sebastian Schwindt

Sediment traps are used for the protection of urban settlements at rivers in mountainous regions. These structures aim at the retention of sediment in the case of hazardous floods, but existing sediment traps tend to retain sediment also when the discharge ...

EPFL2017

Transport time scales in soil erosion modelling

David Andrew Barry, Seifeddine Jomaa, Mohsen Cheraghi

Unlike sediment transport in rivers, erosion of agricultural soil must overcome its cohesive strength to move soil particles into suspension. Soil particle size variability also leads to fall velocities covering many orders of magnitude, and hence to diffe ...

Soil Sci Soc Amer2017

Hysteretic sediment fluxes in rainfall-driven soil erosion: Particle size effects

David Andrew Barry, Seifeddine Jomaa, Mohsen Cheraghi

A detailed laboratory study was conducted to examine the effects of particle size on hysteretic sediment transport under time-varying rainfall. A rainfall pattern composed of seven sequential stepwise varying rainfall intensities (30, 37.5, 45, 60, 45, 37. ...

American Geophysical Union2016