Christophe Ancey

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Associate Professor

christophe.ancey@epfl.ch +41 21 693 32 87 http://lhe.epfl.ch

EPFL ENAC IIC LHE
GC A1 401 (Bâtiment GC)
Station 18
1015 Lausanne

+41 21 693 32 87
+41 21 693 23 75
Office: GC A1 401
EPFL > ENAC > IIC > LHE

Web site: Web site: https://lhe.epfl.ch/

+41 21 693 32 87
EPFL > ENAC > ENAC-SGC > SGC-ENS

+41 21 693 32 87
EPFL > VPA-AVP-DLE > AVP-DLE-EDOC > EDME-ENS

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Administrative data

Fields of expertise

fluid dynamics rheology hydraulics physics of particle transport steep slope flows (avalanches, floods) Risk analysis

Mission

The LHE is a laboratory of environmental fluid mechanics whose research strives toward a better understanding of physical processes in the environment, with particular emphasis on the problems encountered in hydraulics and the study of geophysical flows. The field of research covered within Ancey's team includes the following topics: - Rheology & fluid dynamics of geophysical flow and the resulting hazards, with the objective of modeling natural hazards induced by water such as mudflows and avalanches. - Physics of bed load transport, aiming at better management of sediments in waterways Our major area of interest is the rheology of particle suspensions, mainly the natural suspensions involved in geophysical flows such as avalanches, mudflows, and stream transport of materials. Three major research orientations can be designated 1° Rheology of concentrated suspensions : we are particularly interested in the laws of very concentrated suspension behavior such as granular suspensions, investigating both the problem of determining adapted rheological laws and modeling free surface gravity flows. 2° The inverse problem :very often in rheology, stresses and strains cannot be measured directly; measures must first be taken on the macroscopic scale to then deduce the behavior on the microscopic level. This type of problem is most often within the domain of inverse problems. Our research aims most particularly to propose inverse determination methods either to adjust model coefficients or to deduce the mechanical behavior. 3° Particle entrainment in dilute turbulent suspensions: a major problem in geophysical flows is solid particle entrainment. We are mainly interested in understanding the erosion of a rough particle bed and modeling the phenomenon (Exner equation)

Biography

Christophe Ancey has both a PhD and an engineering degree granted by the Ecole Centrale de Paris and the Grenoble National Polytechnic Institute. Trained as a hydraulics engineer, he did his doctoral work under the supervision of Pierre Evesque from 1994 to 1997 on rheology of granular flows in simple shearing. He was recruited in 1998 as a researcher in rheology at the Cemagref as part of the Erosion Protection team directed by Jean-Pierre Feuvrier, which has since become the laboratoire "Storm Erosion, Snow and Avalanche Laboratory". Parallel to this research activity, with Claude Charlier He set up a consulting firm for engineering contracting called Toraval (www.toraval.fr), which has become the major player in the avalanche field in France. Since 2004, He is a fluid-mechanics professor at EPFL and he is the director of the Environmental Hydraulics Laboratory. He is associate editor of Water Resources Research, one of the leading journal in the field.

Publications

Infoscience publications

2016 - Publications

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Asymmetric breaking size-segregation waves in dense granular free-surface flows

P. Gajjar; K. Van Der Vaart; A. R. Thornton; C. G. Johnson; C. Ancey et al.

Journal Of Fluid Mechanics. 2016. DOI : 10.1017/jfm.2016.170.

Christophe Ancey

Associate Professor

Fields of expertise

Mission

Biography

Publications

Infoscience publications

2016 - Publications

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Asymmetric breaking size-segregation waves in dense granular free-surface flows

2016 - Workshops, conferences

The nature and role of advection in advection-diffusion equations used for modelling bed load transport

2015 - Publications

An Underlying Asymmetry within Particle-size Segregation

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Stochastic-deterministic modeling of bed load transport in shallow water flow over erodible slope: linear stability analysis and numerical simulation

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

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Sediment diffusion in deterministic non-equilibrium bed load transport simulations

2015 - Workshops, conferences

Refractive index matched suspensions as a tool for investigating entrainment by avalanches and debris flows

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Fluid dynamics of basal entrainment by geophysical gravity-driven flows

A viscoplastic lubrication model for entrainment by avalanches and debris flows, and comparison with experiments

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Morphodynamic instability in a novel Saint-Venant-Exner model for bedload transport

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Asymmetric Particle Behavior during Size Segregation

2014 - Publications

A microstructural approach to bed load transport: mean behaviour and fluctuations of particle transport rates

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Bed load transport over a broad range of timescales: Determination of three regimes of fluctuations

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

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

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Sediment transport in mountain rivers

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Un port et des cabanes, à la découverte du lac Baïkal (Sibérie)

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

Reply to Comment on "Effect of Dissolved Organic Matter on the Transformation of Contaminants Induced by Excited Triplet States and the Hydroxyl Radical"

Insertion du littoral dans la maille urbaine (Porto).

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How to verify the precision of density-functional-theory implementations via reproducible and universal workflows

Automated mixing of maximally localized Wannier functions into target manifolds

Les défis de l'expertise moderne

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Pourquoi des modèles de calcul d’avalanche plus complexes n’amènent pas à de meilleurs résultats ?

2014 - Workshops, conferences

Tracking bed load particles in a steep flume: Methods and results.

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Avalanche of fluid in the laboratory: the dam-break problem revisited.

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Asymmetry in Size-Segregation Rates.

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Entraining avalanches on slopes: results from experiments using PIV on viscoplastic gravity currents.

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A model for entrainment in avalanches and debris flows based on PIV measurements of viscous gravity currents.

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Fluctuations of particle transport rates in graved-bed rivers or the quest for equilibrium?

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Analysis of sediment transport from recorded signals of sediments in a gravel-bed river: role of sediment availability

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Breaking Size-Segregation Waves in Granular Avalanches

2013 - Publications

The dam-break problem for concentrated suspensions of neutrally buoyant particles

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Granular suspension avalanches. I. Macro-viscous behavior

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Granular suspension avalanches. II. Plastic regime

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Statistics of bedload transport over steep slopes: Separation of time scales and collective motion

2013 - Workshops, conferences

Bedload transport powered by daily floods: unsteadiness and stochasticity.

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Effect of available entrainable material on a viscous gravity current including run-out characteristics and internal flow properties.

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