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Christophe Ancey

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Related publications (96)

Page 4 of 5

How bar generate sediment transport pulses in gravel-bed channels

Christophe Ancey, Blaise Etienne Marceau Dhont, Ivan Pascal

We ran flume experiments with constant water dis- charge and sediment feed rate at the inlet. Experi- ments were conducted over long times (typically 600 h). The bars migrated downstream intermittently, producing the most important pulses. When the bar pos ...

IAHR2018

Do Antidune Trains Undergo Morphological Changes When These Bedforms Migrate Upstream?

Christophe Ancey, Ivan Pascal

Upstream migrating antidunes develop in streams under supercritical flow conditions. These bedforms are often organised in trains (i.e. sequences of well-developed antidunes). In shallow flows over coarse sediments, the dynamics of a single antidune can be ...

Madrid2022

Automated grain sizing from uncrewed aerial vehicles imagery of a gravel-bed river: Benchmarking of three object-based methods

Christophe Ancey, Ivan Pascal, Raphaël Miazza

Measuring grain sizes in gravel-bed rivers is crucial when studying river dynamics and sediment transport. Automated methodologies have been developed in recent years for detecting individual grains and measuring their size on digital imagery. These object ...

2024

The dam-break problem for viscous fluids in the high-capillary-number limit

Christophe Ancey, Steve Cochard, Nicolas Andreini

Experiments were undertaken to investigate dam-break flows where a finite volume of highly viscous fluid (glucose with viscosity μ ≈ 350 Pa s) maintained behind a lock gate was released into a horizontal or inclined flume. The resulting sequence of flow-de ...

Cambridge University Press2009

Granular suspension avalanches. II. Plastic regime

Christophe Ancey, Nicolas Andreini, Gaël Epely Chauvin

We present flume experiments showing plastic behavior for perfectly density-matched suspensions of non-Brownian particles within a Newtonian fluid. In contrast with most earlier experimental investigations (carried out using coaxial cylinder rheometers), w ...

Amer Inst Physics2013

Monitoring geomorphological changes due to debris flows in mountain rivers using UAV: exploiting similarities between Alpine and Andean regions

Christophe Ancey, Tomás Alfredo Trewhela Palacios

Definition of proper methodologies for unmanned aerial vehicle (UAV) to monitor debris flows will be done in two workshops: one in each participant institution. The objective is to do field demonstrations and measurements to exploit similarities between Al ...

2018

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

Hongbo Ma, Christophe Ancey, Joris Heyman, François Mettra

Steep slope streams show large fluctuations of sediment discharge across several time scales. These fluctuations may be inherent to the internal dynamics of the sediment transport process. A probabilistic framework thus seems appropriate to analyze such a ...

American Geophysical Union2013

Are Bedload Transport Pulses in Gravel Bed Rivers Created by Bar Migration or SedimentWaves?

Christophe Ancey, Blaise Etienne Marceau Dhont

Bedload transport exhibits considerable spatial and temporal variability, as reflected by large fluctuations of transport rates. Among the various mechanisms proposed for explaining this variability, bedform migration is often cited as the main cause. We t ...

2018

Bedload transport: a walk between randomness and determinism. Part 2. Challenges and prospects

Christophe Ancey

By the late nineteenth century, the scientific study of bedload transport had emerged as an offshoot of hydraulics and geomorphology. Since then, computing bedload transport rates has attracted considerable attention, but whereas other environmental scienc ...

Taylor & Francis Ltd2020

Tracking the free surface of time-dependent flows: Image processing for the dam-break problem

Christophe Ancey, Steve Cochard

The dam-break problem (i.e., the sudden release of a given volume of fluid down a slope) has attracted a great deal of attention from mechanicians and physicists over the past few years, with particular interest devoted to the free-surface profile and the ...

Springer Verlag2008

Refractive-index and density matching in concentrated particle suspensions: a review

Christophe Ancey, Nicolas Andreini, Sébastien Wiederseiner, Gaël Epely Chauvin

Optical measurement techniques such as particle image velocimetry (PIV) and laser Doppler velocimetry (LDV) are now routinely used in experimental fluid mechanics to investigate pure fluids or dilute suspensions. For highly concentrated particle suspension ...

Springer-Verlag2011

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

Christophe Ancey, Nicolas Andreini, Gaël Epely Chauvin

This paper addresses the dam-break problem for particle suspensions, that is, the flow of a finite volume of suspension released suddenly down an inclined flume. We were concerned with concentrated suspensions made up of neutrally-buoyant non-colloidal par ...

Cambridge University Press2013

An Underlying Asymmetry within Particle-size Segregation

Christophe Ancey, Nicolas Andreini, Gaël Epely Chauvin, Kasper van der Vaart

We experimentally study particle scale dynamics during segregation of a bidisperse mixture under oscillatory shear. Large and small particles display an underlying asymmetry that is dependent on the local particle concentration, with small particles segreg ...

American Physical Society2015

Internal dynamics of Newtonian and viscoplastic fluid avalanches down a sloping bed

Christophe Ancey, Nicolas Andreini, Gaël Epely Chauvin

We experimentally investigated the spreading of fluid avalanches (i.e., fixed volumes of fluid) down an inclined flume. Emphasis was given to the velocity field within the head. Using specific imaging techniques, we were able to measure velocity profiles w ...

2012

An overview on mathematical models for modelling snow avalanches

Christophe Ancey

2006

Two-dimensional motion of a set of particles in a free surface flow with image processing

Christophe Ancey, Peter Frey

Springer2006

Improved SPH methods for simulating free surface flows of viscous fluids

Christophe Ancey, Aurèle Parriaux, Jiannong Fang, Martin Rentschler

2009

Bedload transport: a walk between randomness and determinism. Part 1. The state of the art

Christophe Ancey

This paper outlines the various approaches used to calculate bedload transport. As bedload transport exhibits considerable spatial and temporalvariations, computing the bedload transport rates and morphological changes experienced by streambeds is difficul ...

Taylor & Francis Ltd2020

Front dynamics of a water surge at high Reynolds number: Similarity solutions to the Saint-Venant equations

Christophe Ancey, Steve Cochard, Martin Rentschler, Sébastien Wiederseiner

2006

Accurate measurements of free-surface in the dam-break problem

Christophe Ancey, Steve Cochard

Taylor & Francis2006