Publications associées à Fabrication of microfluidic mixers with varying topography in glass using the powder blasting process

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

Different erosion and entrainment mechanisms in snow avalanches

Betty Sovilla, Johan Alexandre Philippe Gaume, 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

Modified full-face snorkel masks as reusable personal protective equipment for hospital personnel

Patrick Gerber, Nitin Arora, Mélanie Thérèse Marie Hannebelle

Here we adapt and evaluate a full-face snorkel mask for use as personal protective equipment (PPE) for health care workers, who lack appropriate alternatives during the COVID-19 crisis in the spring of 2020. The design (referred to as Pneumask) consists of ...

2021

Multiscale simulation of erosive wear in a prototype-scale Pelton runner

François Avellan, Ebrahim Jahanbakhsh, Sebastián Camilo Leguizamón Sarmiento, Siamak Alimirzazadeh

The technical capacity to predict the erosion process is instrumental for the optimization of the runner designs and operation strategies of hydroelectric plants. A multiscale model of erosion recently formulated by the authors and validated on a laborator ...

Pergamon-Elsevier Science Ltd2020

Reusability of filtering facepiece respirators after decontamination through drying and germicidal UV irradiation

David Vernez, Véronique Michaud, Guillaume Suarez, Kiattisak Batsungnoen

Introduction During pandemics, such as the SARS-CoV-2, filtering facepiece respirators plays an essential role in protecting healthcare personnel. The recycling of respirators is possible in case of critical shortage, but it raises the question of the effe ...

2020

FVPM numerical simulation of the effect of particle shape and elasticity on impact erosion

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

The erosion of hydraulic machines by solid particle impacts is a widespread problem that leads to outage for expensive repairs, efficiency reduction, and cavitation enhancement. Numerical simulations can be used to study the phenomenon, provided they featu ...

ELSEVIER SCIENCE SA2019

Multiscale Modeling and Simulation of Erosive Wear in Pelton Turbines

Sebastián Camilo Leguizamón Sarmiento

Hydropower has been identified as a key technology to mitigate climate change due to its very low lifecycle greenhouse gas emission intensity and its capacity to integrate intermittent renewable energy sources such as wind and solar into the electrical gri ...

EPFL2019

Simulation of the hydroabrasive erosion of a bucket: A multiscale model with projective integration to circumvent the spatio-temporal scale separation

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

The hydroabrasive erosion of hydraulic machine components, especially Pelton buckets and needles, is a widespread problem that entails significant costs. The multiscale nature of the process renders its simulation very computationally demanding unless spec ...

IOP PUBLISHING LTD2019

Preferential Deposition of Snow and Dust Over Hills: Governing Processes and Relevant Scales

Marc Parlange, Michael Lehning, Marco Giovanni Giometto, Francesco Comola

Preferential deposition of snow and dust over complex terrain is responsible for a wide range of environmental processes and accounts for a significant source of uncertainty in the surface mass balances of cold and arid regions. Despite the growing body of ...

2019

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

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

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

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

Erosion, screening, and migration of tungsten in the JET divertor

Patrick Blanchard, Basil Duval, Ambrogio Fasoli, Yves Martin, Richard Pitts, Olivier Sauter, Henri Weisen, Stefano Coda, Marco Wischmeier, Jan Horacek, Yann Camenen, Jonathan Graves, Duccio Testa, Mikhail Maslov, Javier García Hernández, David Pfefferlé, Dalziel Joseph Wilson, Jonathan Marc Philippe Faustin, Federico Nespoli, Hamish William Patten, Nicola Vianello, Antonio José Pereira de Figueiredo, Samuel Lanthaler, Liang Yao, Cristian Sommariva, Davide Galassi, Alessandro Pau, Yao Zhou, Otto Asunta, Bernhard Sieglin

The erosion of tungsten (W), induced by the bombardment of plasma and impurity particles, determines the lifetime of plasma-facing components as well as impacting on plasma performance by the influx of W into the confined region. The screening of W by the ...

IOP Publishing Ltd2019

Experiments with sediment replenishment in a residual flow reach: Comparison of field datawith laboratory experiments

Anton Schleiss, Mário Jorge Rodrigues Pereira Da Franca, Christopher Robinson, Severin Stähly

Hydropower is an important pillar of the electricity production in Switzerland and its extension is planned in the next decades. Therefore, a more sustainable management of hydropower plants is needed. Sediment replenishment combined with artificially-trig ...

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

Hydrodynamics of mountain-river confluences and its relationship to sediment transport

Mário Jorge Rodrigues Pereira Da Franca, Sebastián Guillén Ludeña

Mountain confluences are characterized by narrow and steep tributaries that provide important sediment load to the confluence, whereas themain channel supplies the dominant flow discharge. This results in a marked bed discordance between the tributary and ...

American Geophysical Union2017

Impact of rotating and fixed nozzles on vortex breakdown in compressible swirling jet flows

Leonhard Kleiser, François Gallaire

Vortex breakdown of swirling, round jet flows is investigated in the compressible, subsonic regime by means of Direct Numerical Simulation (DNS). This is achieved by solving the compressible Navier-Stokes equations on a cylindrical grid using high-order sp ...

Elsevier2016

Thermal energy in dry snow avalanches

Michael Lehning, Walter Steinkogler

Avalanches can exhibit many different flow regimes from powder clouds to slush flows. Flow regimes are largely controlled by the properties of the snow released and entrained along the path. Recent investigations showed the temperature of the moving snow t ...

Copernicus Gesellschaft Mbh2015

Experimental characterization of vegetation uprooting by flow

Benoît Crouzy, Paolo Perona, Katharina Maria Edmaier

We investigate vegetation uprooting by flow for Avena sativa seedlings with stem-to-sediment size ratio close to unity and vanishing obstacle-induced scouring. By inducing parallel riverbed erosion within an experimental flume, we measure the time-to-uproo ...

2015

Influence of snow cover properties on avalanche dynamics

Walter Steinkogler

Snow avalanches are a direct thread to many mountain communities around the world and already small avalanches can endanger traffic routes and result in loss of life or property. Their destructive power depends, among other things, on the overall mass and ...

EPFL2015

Simulation of Silt Erosion Using Particle-Based Methods

Ebrahim Jahanbakhsh

Increasing demand for clean sources of energy have forced electricity providers to paymore attention to their hydropower assets. Silt erosion is a destructive phenomenon that may occur in hydropower plants. The power plant subjected to silt erosion require ...

EPFL2014