A5009046572- Hydrology and Sediment Transport Processes
- Soil erosion and sediment transport
- Landslides and related hazards
- Geological formations and processes
- Hydrology and Watershed Management Studies
- Geology and Paleoclimatology Research
- Groundwater flow and contamination studies
- Granular flow and fluidized beds
- Fluid Dynamics and Turbulent Flows
- Hydraulic flow and structures
- Aeolian processes and effects
- Flood Risk Assessment and Management
- Cryospheric studies and observations
- Groundwater and Isotope Geochemistry
- Coastal and Marine Dynamics
- Theoretical and Computational Physics
- Water Systems and Optimization
- Soil and Unsaturated Flow
- Particle Dynamics in Fluid Flows
- Lattice Boltzmann Simulation Studies
- Geotechnical and Geomechanical Engineering
- earthquake and tectonic studies
- Underwater Acoustics Research
- Aerodynamics and Acoustics in Jet Flows
- Material Dynamics and Properties
Institut de physique du globe de Paris
2016-2025
Université Paris Cité
2013-2022
Centre National de la Recherche Scientifique
2012-2022
Institut Pierre-Gilles de Gennes pour la Microfluidique
2020
Sorbonne Paris Cité
2011-2019
Délégation Paris 7
2011-2018
Laboratoire de Dynamique des Fluides
2010-2013
Planetary Science Institute
2009
Institut Jean Le Rond d'Alembert
2009
Sorbonne Université
1999-2006
We report an experimental investigation of the motion bed load particles under steady and spatially uniform turbulent flow above a flat sediment grain size. Using high‐speed video imaging system, we recorded trajectories moving measured their velocity length duration flights, as well surface density particles. Our observations show that entrained exhibit intermittent composed succession periods “flight” rest. During one flight, particle may go through phases reptation, during which it moves...
Core Ideas OZCAR is a network of sites studying the critical zone. covers various disciplines. will help disciplines to work together for better representation and modeling The French zone initiative, called (Observatoires de la Zone Critique–Application et Recherche or Critical Observatories–Application Research) National Research Infrastructure (RI). OZCAR‐RI instrumented sites, bringing 21 pre‐existing research observatories monitoring different compartments situated between “the rock...
The transient surface flow occurring when a cylindrical pile of dry granular material is suddenly allowed to spread on horizontal plane investigated experimentally as function the released mass M, initial aspect ratio cylinder pile, properties underlying substrate (smooth or rough, rigid erodible) and bead size. Two different regimes leading three deposit morphologies are observed a, whatever For a≲3, spreads through an avalanche its flanks producing either truncated cone conical deposits....
We report the results of an experimental investigation flow induced by collapse a column granular material (glass beads diameter d) over horizontal surface. Two different setups are used, namely, rectangular channel and semicircular tube, allowing us to compare two-dimensional axisymmetric flows, with particular focus on internal structure. In both geometries dynamics deposit morphologies observed depend primarily initial aspect ratio a=Hi∕Li, where Hi is height Li its length along...
Cliff collapse is an active geomorphological process acting at the surface of Earth and telluric planets. Recent laboratory studies have investigated initially cylindrical granular mass along a rough horizontal plane for different initial aspect ratios = H i / R , where are height radius, respectively. A numerical simulation these experiments performed using minimal depth‐integrated model based on long‐wave approximation. dimensional analysis equations shows that such exhibits scaling laws...
We study experimentally and theoretically the downward vertical displacement of one miscible fluid by another lighter in gap a Hele-Shaw cell at sufficiently high velocities for diffusive effects to be negligible. Under certain conditions on viscosity ratio, M , normalized flow rate, U this results formation two-dimensional tongue injected fluid, which is symmetric with respect midplane. Thresholds rate ratio exist above two- dimensional destabilizes, giving rise three-dimensional pattern....
We investigate experimentally the statistical properties of bedload transport induced by a steady, uniform, and laminar flow. focus chiefly on lateral transport. The analysis is restricted to experiments where flow-induced shear stress just above threshold for sediment find that, in this regime, concentration moving particles low enough neglect interactions between themselves. can therefore represent as thin layer independent walkers travelling over bed surface. In addition their downstream...
Abstract. More than a century of experiments have demonstrated that many features natural rivers can be reproduced in the laboratory. Here, we revisit some these to cast their results into framework threshold-channel theory developed by Glover and Florey (1951). In all analyze, typical size channel conforms this theory, regardless river's planform (single-thread or braiding). respect, laboratory behave exactly like counterpart. Using finding, reinterpret Stebbings (1963). We suggest sediment...
We study the downward miscible displacement of a fluid by lighter and less viscous one in gap Hele-Shaw cell. For sufficiently large velocities, well-defined interface separates two fluids. As long as velocity or viscosity ratio are below critical value, has shape tongue symmetric across gap. ratios larger than estimated at 1.5, there exists velocity, above which becomes unstable, leading to new 3D pattern involving regularly spaced fingers wavelength about 5 times cell thickness. delineate...
The use of microscale experimental rivers (with flow depths the order a few millimeters) to investigate natural processes such as alluvial fans dynamics, knickpoints migration, and channel morphologies, meandering braiding has become increasingly popular in recent years. This raises need address issue how extrapolate results from at which is laminar scale turbulent rivers. We this question by performing measurements average velocity sediment transport an river. correctly predicted...
Despite several decades of investigations, accounting for the effect wide range grain sizes composing bed rivers on bedload transport remains a challenging problem. We investigate this problem by studying experimentally influence size distribution in simple configuration bimodal sediment composed mixture 2 populations quartz grains D 1 = 0.7 ± 0.1 mm and 2.2 0.4 mm, respectively. The experiments are carried out tilted rectangular flume inside which is sheared steady spatially uniform...
During a rainfall event, water infiltrates into the ground where it accumulates in porous rocks. This accumulation pushes underlying groundwater towards neighbouring streams, runs to sea. After rain has stopped, aquifer gradually releases its excess water, as table relaxes, until next rain. In absence of recharge, would eventually reach horizontal equilibrium position. The volume stored above this level, which we call active volume, sustains river between two events. article, use an...
In most environments, rainfall infiltrates into the porous ground, and forms a body of groundwater which flows neighbouring river network. The discharge is particularly strong near heads where it triggers seepage erosion, causing existing channels to grow headward. Occasionally, this process initiates development new branches, leading formation ramified Because erosion slow, drainage networks take hundreds thousands years build. Therefore, observing their evolution in field difficult if not...
The interaction of flow with an erodible bed in alluvial rivers and deep-sea channels gives rise to a wide range self-formed morphologies, including channels, ripples, dunes, antidunes, alternate bars, multiple-row meandering braiding. As the is invariably turbulent field manifestations these there has been tendency assume that turbulence necessary for them form. While undoubtedly important influence when it present, not any features. Indeed, all features can be formed by morphodynamic...
The prediction of the runout length L large dry debris flows has long been subject a considerable research effort, primarily due to obvious concern caused by their destructive power. One seemingly well established feature is increase mobility ℳ rock avalanche, defined as ratio distance fall height, with its volume V . physical nature this lubrication mechanism remains however controversial. In paper, we analyse field data and discrete numerical simulations granular demonstrate geometrical...
In this paper we present chemical composition data for major elements in rivers from three islands of the Lesser Antilles. The Antilles are a tropical volcanic subduction arc and characterized by steep gradients relief, bedrock age precipitation. They constitute natural laboratory where response weathering engine to large variations runoff can be understood. Data indicate that extremely variable (40-430 t/km^2^/a) CO~2~ consumption (300-3500.10^3^ mol/km^2^/a) rates, amongst highest found on...
An experimental and theoretical study of a one-dimensional model an alluvial fan provides insight into features familiar two-dimensional phenomenon. In their model, the authors show that grows quasistatically at moderate sediment discharge maintains its slope just above critical threshold for transport.
We study experimentally the downward vertical displacement of one miscible fluid by another in a pipe at sufficiently high velocities for diffusive effects to be negligible. For certain viscosity ratios and flow rates, interface between two fluids can destabilize. determine dimensionless rate Uc above which instability is triggered its dependence on viscous ratio M, resulting stability map Uc=Uc(M). Two different modes have been observed: an asymmetric “corkscrew” mode axisymmetric one....
Abstract Submarine megafans and their associated canyons have long attracted the attention of a large community in earth sciences because they record history past erosional processes. As such, morphology sedimentary infill may be use to unravel climatic tectonic evolution. Yet despite an important corpus research on structural characteristics we lack well accepted quantitative description for dynamics formation growth these systems. One main reasons this lies our inability successfully...
A viscous fluid flowing over plastic grains spontaneously generates single-thread channels. With time, these laminar analogues of alluvial rivers reach a reproducible steady state, showing well-defined width and cross section. In the absence sediment transport, their shape conforms with threshold hypothesis which states that, at equilibrium, combined effects gravity flow-induced stress maintain bed surface motion. This theory explains how channel selects its size slope for given discharge....