Publications by Christophe Ancey

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In the spring of 1818, ice avalanches from the Gietro Glacier created an ice dam, which in turn formed a glacial lake in the Drance Valley (Canton of Valais, Switzerland). Today, its maximum volume is estimated to have been 25x10(6) m(3). Cantonal authorit ...

We investigate the entrainment, deposition and motion of coarse spherical particles within a turbulent shallow water stream down a steep slope. This is an idealization of bed-load transport in mountain streams. Earlier investigations have described this ki ...

This paper concerns a model of bed load transport, which describes the advection and dispersion of coarse particles carried by a turbulent water stream. The challenge is to develop a microstructural approach that, on the one hand, yields a parsimonious des ...

A general continuum theory for particle size segregation and diffusive remixing in polydisperse granular avalanches is formulated using mixture theory. Comparisons are drawn to existing segregation theories for bi-disperse mixtures and the case of a ternar ...

This paper presents image velocimetry measurements on turbulent flows adjacent to a permeable bed made of randomly packed glass particles. For measuring flow velocities inside the bed, the refractive index of the glass particles was matched with that of th ...

There is a paradox in the relationship between bedload transport rates and flow variables: laboratory and field studies have reported on how bedload transport rates depend on flow variables through a power law, but none of the empirical laws fitted to the ...

Steep streams involve shallow, supercritical turbulent flows over a permeable bed made up of coarse particles. They usually exhibit higher flow resistance and stronger mass and momentum exchanges between the stream and subsurface flow than low-gradient str ...

Steep streams on rough beds are generally characterised by supercritical flow conditions under which antidunes can develop and migrate over time. In this paper, we present flume experiments that we conducted to investigate the variability of antidune geome ...

Debris and pyroclastic flows often have bouldery flow fronts, which act as a natural dam resisting further advance. Counter intuitively, these resistive fronts can lead to enhanced run-out, because they can be shouldered aside to form static levees that se ...

The objective of this review is to examine how the concept of plasticity is used in geophysical fluid dynamics. Rapid mass movements such as snow avalanches or debris flows involve slurries of solid particles (ice, boulder, clay, etc.) within an interstiti ...

This paper examines the importance of particle diffusion relative to advection in bed load transport. Particle diffusion is not included in existing approaches to bedload transport. Based on recent advances in the probabilistic theory of sediment transport ...

We report experimental results related to the dam-break problem for viscoplastic fluids. Using image processing techniques, we were able to accurately reconstruct the free-surface evolution of fixed volumes of fluid suddenly released a plane. We used Carbo ...

Understanding the physical processes involved in snow avalanche‐obstacle interaction is essential to be able to estimate the pressure exerted on structures. Although avalanche impact pressure has been measured in field experiments for decades, the underlyi ...

Particle segregation is a widespread process that affects particle composition in granular materials. Particles tend to segregate into distinct regions according to their size, density, and shape. To date, most studies investigate particles segregating in ...

Measuring bedload transport rates usually involves measuring the flux of sediment or collecting sediment during a certain interval of time Δt. Because bedload transport rates exhibit significant non‐Gaussian fluctuations, their time‐averaged rates depend a ...

We experimentally studied the flow behavior of a fixed volume of granular suspension, initially contained in a reservoir and released down an inclined flume. Here “granular suspension” refers to a suspension of non-Brownian particles in a viscous fluid. De ...

The idea that snow avalanches might behave as granular flows, and thus be described as Coulomb fluid flows, came up very early in the scientific study of avalanches, but it is not until recently that field evidence has been provided that demonstrates the r ...

Understanding the relationship between bedload transport and morphological changes is crucial in braided river systems, particularly those on steep slopes. Despite significant research efforts in recent decades, unraveling this interplay remains a complex ...

When a mixture of particles, which differ in both their size and their density, avalanches downslope, the grains can either segregate into layers or remain mixed, dependent on the balance between particle-size and particle-density segregation. In this pape ...

Particles of differing sizes are notoriously prone to segregation in shear driven flows under the action of gravity. This has important implications in many industrial processes, where particle-size segregation can lead to flow problems and reduced product ...

Christophe Ancey

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Hydraulic Reconstruction of the 1818 Gietro Glacial Lake Outburst Flood

Entrainment and motion of coarse particles in a shallow water stream down a steep slope

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

Multi-component particle size segregation in shallow granular avalanches

Scanning PIV of turbulent flows over and through rough porous beds using refractive index matching

Scaling behavior of bedload transport: what if Bagnold was right?

An experimental investigation of turbulent free-surface flows over a steep permeable bed

The variability of antidune morphodynamics on steep slopes

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

Plasticity and geophysical flows: A review

Particle diffusion in non-equilibrium bedload transport simulations

Experimental investigation of the spreading of viscoplastic fluids on inclined planes

Decoupling the role of inertia, friction and cohesion in dense granular avalanche pressure build‐up on obstacles

Particle segregation in an annular shear cell

Estimating Mean Bedload Transport Rates and Their Uncertainty

Granular suspension avalanches. I. Macro-viscous behavior

Monte Carlo calibration of avalanches described as Coulomb fluid flows

Probabilistic Modeling of Sediment Dynamics in Braided River Systems

Particle-size and -density segregation in granular free-surface flows

An experimental scaling law for particle-size segregation in dense granular flows