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Christophe Ancey

Cette personne a quitté l’EPFL

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Publications associées (96)

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Statistical description of sediment transport experiments

Christophe Ancey, Peter Frey

A longstanding problem in the study of sediment transport in gravel-bed rivers is related to the physical mechanisms governing bed resistance and particle motion. To study this problem, we investigated the motion of coarse spherical glass beads entrained b ...

2006

Temporal Prediction of Landslide-Generated Waves Using a Theoretical-Statistical Combined Method

Christophe Ancey, Zhenzhu Meng

For the prediction of landslide-generated waves, previous studies have developed numerous empirical equations to express the maximums of wave characteristics as functions of slide parameters upon impact. In this study, we built the temporal relationship be ...

MDPI2023

Viscoplastic dambreak waves: review of simple computational approaches and comparison with experiments

Christophe Ancey, Nicolas Andreini, Gaël Epely Chauvin

We investigated the dam-break problem for Herschel-Bulkley fluids: a fixed volume of a viscoplastic material (a polymeric gel called Carbopol ultrez 10) was released and flowed down an inclined flume. Using Particle Image Velocimetry techniques, we measure ...

Elsevier2012

The dam-break problem for eroding viscoplastic fluids

Christophe Ancey, Belinda Margaret Bates

Natural gravity-driven flows can increase in volume by eroding the bed on which they descend. This process is called basal entrainment and is thought to play a key role in the bulk dynamics of geophysical flows. Although its study is difficult using field ...

Elsevier2017

The effects of slide cohesion on impulse-wave formation

Christophe Ancey, Zhenzhu Meng

Experimental studies of impulse-wave formation have mostly used rigid blocks or granular materials to mimic landslides at the laboratory scale. These studies have deduced that material deformability plays a key part in wave formation: the more rigid the sl ...

2019

Visualization of the internal flow properties and the material exchange interface in an entraining viscous Newtonian gravity current

Christophe Ancey, Belinda Margaret Bates

In order to simulate a simple entraining geophysical flow, a viscous Newtonian gravity current is released from a reservoir by a dam-break and flows along a rigid horizontal bed until it meets a layer of entrainable material of finite depth, identical to t ...

Springer Verlag2014

Basal entrainment by Newtonian gravity-driven flows

Christophe Ancey, Nicolas Andreini, Belinda Margaret Bates

Gravity-driven flows can erode the bed along which they descend and increase their mass by a factor of 10 or more. This process is called "basal entrainment." Although documented by field observations and laboratory experiments, it remains poorly understoo ...

Amer Inst Physics2016

Stochastic bedload transport in mountain streams

Christophe Ancey

Describing bedload transport as a stochastic process is an idea that emerged in the 1930s with the pioneering work of Einstein. For a long time, the stochastic approach attracted marginal attention, but the situation has radically changed over the last dec ...

EDP Sciences2018

Vegetation Submergence Effects on Bedload Transport Rate

Christophe Ancey

We conducted a series of laboratory experiments to investigate the impact of vegetation on bedload transport rates depending on submergence. In the experiments, we used aluminum rods to simulate rigid vegetation, with vegetation submergence ratios (i.e., t ...

2024

The Kulikovskiy-Sveshnikova-Beghin Model of Powder Snow Avalanches: Development and Application

Christophe Ancey

A simple theoretical model, the Kulikovskiy–Sveshnikova–Beghin (KSB) model, is outlined, describing the motion of a particle cloud moving down an incline. This model includes both the entrainment of surrounding ambient fluid and the entrainment of particle ...

2007

Image processing for the study of bedload transport of two-size spherical particles in a supercritical flow

Christophe Ancey

Bedload sediment transport of two-size coarse spherical particle mixtures in a turbulent supercritical flow was analyzed with image and particle tracking velocimetry algorithms in a two-dimensional flume. The image processing procedure is entirely presente ...

Springer Verlag2010

Spatial correlations in bed load transport: Evidence, importance, and modeling

Christophe Ancey, Joris Heyman, François Mettra, Hongbo Ma

This article examines the spatial {dynamics of bed load particles} in water. We focus particularly on the fluctuations of particle activity, which is defined as the number of moving particles per unit bed {length}. Based on a stochastic model recently prop ...

Amer Geophysical Union2014

Stochastic interpretation of the advection diffusion equation and its relevance to bed load transport

Christophe Ancey, Joris Heyman

The advection diffusion equation is one of the most widespread equations in physics. It arises quite often in the context of sediment transport, e.g., for describing time and space variations in the particle activity (the solid volume of particles in motio ...

American Geophysical Union2015

A conveyor belt experimental setup to study the internal dynamics of granular avalanches

Christophe Ancey, Tomás Alfredo Trewhela Palacios

This paper shows how a conveyor belt setup can be used to study the dynamics of stationary granular flows. To visualise the flow within the granular bulk and, in particular, determine its composition and the velocity field, we used the refractive index mat ...

SPRINGER2021

Instability of Antidune Incipience under Low Submergence Conditions

Christophe Ancey, Ivan Pascal, Sofi Farazande

Investigating the stability of river bedforms is essential for understanding their occurrence and evolution over time. Whereas the formation of ripples and dunes has been extensively studied [1, 2], little is known about antidune stability in the early sta ...

2024

Continuous Monitoring of Bed-Load Transport in a Laboratory Flume Using an Impact Sensor

Christophe Ancey, Blaise Etienne Marceau Dhont, Gauthier Paul Daniel Marie Rousseau

Bed-load transport rate in gravel-bed rivers shows large non-Gaussian fluctuations, even under steady flow conditions. The development of high-resolution measurement techniques during the last two decades creates research opportunities to study the intermi ...

American Society of Civil Engineers2017

An exact solution for ideal dam-break floods on steep slopes

Christophe Ancey, Martin Rentschler

Dam-break floods on steep slopes occur in diverse settings. They may result from failure of either natural or man-made dams, and they have been responsible for the loss of thousands of lives [Costa, 1988]. Recent disasters resulting from dam-break floods o ...

American Geophysical Union2008

Stochastic modeling in sediment dynamics: Exner equation for planar bed incipient bed load transport conditions

Christophe Ancey

Even under flow equilibrium conditions, river bed topography continuously evolves with time, producing trains of irregular bed forms. The idea has recently emerged that the variability in the bed form geometry results from some randomness in sediment flux. ...

American Geophysical Union2010

Bar dynamics and sediment transport pulses in gravel-bed channels

Christophe Ancey, Blaise Etienne Marceau Dhont

Mountain rivers exhibit sediment transport rate fluctuations that often cover more than two orders of magnitude. Bedform migration is often cited as the key process that causes giant fluctuations in the sediment transport rate. To quantify the effect of be ...

EDP Sciences2018

Front dynamics of supercritical non-Boussinesq gravity currents

Christophe Ancey, Steve Cochard, Martin Rentschler, Sébastien Wiederseiner

In this paper, we seek similarity solutions to the shallow water (Saint-Venant) equations for describing the motion of a non-Boussinesq, gravity-driven current in an inertial regime. The current is supplied in fluid by a source placed at the inlet of a hor ...

American Geophysical Union2006