Publications associées à Aeolian processes

Understanding snow saltation parameterizations: lessons from theory, experiments and numerical simulations

Michael Lehning, Armin Sigmund, Daniela Brito Melo

Drifting and blowing snow are important features in polar and high mountain regions. They control the surface mass balance in windy conditions and influence sublimation of snow and ice surfaces. Despite their importance, model representations in weather an ...

2024

Snow transport in extreme environments: from small to large scale modeling

Daniela Brito Melo

The cold regions on Earth, such as the polar and high mountain regions, are snow covered for at least a part of the year. These snow-covered surfaces are highly dynamic, particularly under the influence of strong winds. The aeolian or wind-driven transport ...

EPFL2023

Insights Into the Dynamics of Vegetated Alternate Bars by Means of Flume Experiments

Giulio Calvani

Alternate bars are bedforms recognizable in straight or weakly curved channels as a result of riverbed instability. The length and height of alternate bars scale with the river width and the water depth, respectively. During low water stages, alternate bar ...

American Geophysical Union2023

Mechanistic 2D flow-erosion modelling of vegetated river banks

Giovanni De Cesare, Paolo Perona, Massimiliano Schwarz

We present a simple, vertically-explicit 2D model of river bank erosion that also takes the effect of sediment stabilization by plant roots into account. The model is solved in quasi-analytical form for an exemplary non-stationary hydrograph temporal signa ...

2023

Spectroscopic characterisation of TCV divertor towards a detached regime

Lorenzo Martinelli

The challenge of power exhaust of the high heat and particle fluxes foreseen for ITER and the forthcoming nuclear fusion reactors can be mitigated by operating in a detached divertor regime. This regime has been the object of three decades of studies, as i ...

EPFL2023

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

Density currents driven by differential cooling in lakes: occurrence, dynamics and implications for littoral-pelagic exchange

Tomy Doda

Cross-shore flows exchange water laterally in lakes, with ecological implications for the ecosystem. One example is the convective circulation induced by differential cooling, also known as the thermal siphon. This lateral flow forms when the sloping sides ...

EPFL2022

Different erosion and entrainment mechanisms in snow avalanches

Johan Alexandre Philippe Gaume, Betty Sovilla, Xingyue Li

Erosion significantly affects the dynamics of gravity-driven mass flows. In snow avalanches, the snow cover can be substantially eroded but only partially entrained, however, there are very limited investigations to substantiate this difference. Here, we s ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Improved framework to estimate travel time and derived distributions in hydrological control volumes

Mitra Asadollahi

Crossing properties of soil saturation, defined as the duration and excursion of soil saturation below and above certain thresholds, are key variables to ecosystem functioning and evolution by primarily influencing the plant and soil microbes physiological ...

EPFL2022

Benthic Biofilms in Glacier-Fed Streams from Scandinavia to the Himalayas Host Distinct Bacterial Communities Compared with the Streamwater

Tom Ian Battin, Hannes Markus Peter, Susheel Bhanu Busi, Grégoire Marie Octave Edouard Michoud, Leïla Ezzat, Massimo Bourquin, Matteo Tolosano, Emmy Marie Oppliger, Jade Brandani, Paraskevi Pramateftaki, Virginia Tadei, Vincent Henri De Staercke, Tyler Joe Kohler, Michail Styllas, Stylianos Fodelianakis, Martina Andrea Schön

Microbial life in glacier-fed streams (GFSs) is dominated by benthic biofilms which fulfill critical ecosystem processes. However, it remains unclear how the bacterial communities of these biofilms assemble in stream ecosystems characterized by rapid turno ...

AMER SOC MICROBIOLOGY2022

Three-Dimensional Numerical Modelling of Al-Salam Storm Water Pumping Station in Saudi Arabia

Azin Amini, Azad Koliji

The Al-Salam Pump Station will be constructed in the framework of Jeddah Storm water Masterplan (JSWM) in Saudi Arabia. The station discharges the incoming flow from the Al-Salam storm tunnel to the Red Sea. Its structure includes a circular deep wet well ...

IAHR2022

Experimental Study on Bedload Transport and Bedforms: Behaviour and Interplay in Steep Turbulent Streams

Ivan Pascal

In mountain regions, steep streams play an important role in water and sediment connectivity. In these highly dynamic systems, water flow features, sediment fluxes and stream morphologies are tightly interlinked over a broad range of temporal and spatial s ...

EPFL2022

Wind Transport of Snow Impacts Ka- and Ku-band Radar Signatures on Arctic Sea Ice

Marc Schneebeli Zeugin, David Nicholas Wagner

Wind transport alters the snow topography and microstructure on sea ice through snow redistribution controlled by deposition and erosion. The impact of these processes on radar signatures is poorly understood. Here, we examine the effects of snow redistrib ...

2023

Study of Aerodynamic Grain Entrainment in Aeolian Transport

Aeolian transport controls landform formations on Earth and other planets and crucially affects the atmospheric system. With elaborate wind tunnel measurements, we find that the aerodynamic entrainment rate follows a yet unreported exponential increase in ...

2020

Quasi-stationary flow structure in turbidity currents

Giovanni De Cesare, Shun Nomura

A turbidity current is a particle-laden current driven by density differences due to suspended sediment particles. Turbidity currents can transport large amounts of sediment down slopes over great distances, and play a significant role in fluvial, lake and ...

IRTCES2020

Atomic Scale Investigations into the Origins of Ductility in Mg Alloys

Rasool Ahmad

The industrial applications of Mg, the lightest structural metal, and abundant in Earth's crust, are hampered by its low intrinsic ductility and low fracture toughness at room temperature which is attributed to the underlying less symmetric and plastically ...

EPFL2020

Hydraulic Transport Through Calcite Bearing Faults With Customized Roughness: Effects of Normal and Shear Loading

Marie Estelle Solange Violay, Mateo Alejandro Acosta

Understanding fluid flow in rough fractures is of high importance to large scale geologic processes and to most anthropogenic geo‐energy activities. Here we conducted fluid transport experiments on Carrara marble fractures with a novel customized surface t ...

2020

Density-dependent solute transport in a layered hyporheic zone

David Andrew Barry, Mohsen Cheraghi, Qihao Jiang, Jing Xu

Hyporheic exchange is affected by bedform geometry, which induces complex flow paths within the bedform. Additional factors that influence flow and solute transport in the hyporheic zone are layered profile sediments and density-driven flow. This study exp ...

ELSEVIER SCI LTD2020

Understanding snow bedform formation by adding sintering to a cellular automata model

Varun Sharma, Michael Lehning, Louise Braud

Cellular-automata-based modelling for simulating snow bedforms and snow deposition is introduced in this study. The well-known ReSCAL model, previously used for sand bedforms, is adapted for this purpose by implementing a simple sintering mechanism. The ef ...

Copernicus GmbH2019

Multiscale Simulation of the Hydroabrasive Erosion of a Pelton Bucket: Bridging Scales to Improve the Accuracy

François Avellan, Ebrahim Jahanbakhsh, Audrey Paulette Solange Maertens, Sebastián Camilo Leguizamón Sarmiento, Siamak Alimirzazadeh

Erosive wear of hydraulic machines is a common issue, which results in efficiency degradation, the enhancement of cavitation, and the need for expensive maintenance. Although numerical simulations of the erosion process could be very useful, both for under ...

2019