We introduce a system of shallow water-type equations to model laboratory experiments particle-laden flows. explore homogeneous liquid–solid suspensions fine, non-cohesive, monodisperse glass beads propagating as an equivalent fluid that progressively sediments and forms growing deposit at the bottom smooth channel simultaneously creates thin layer pure liquid surface. The flow front displays three phases transport: brief gravitational collapse where no sedimentation occurs, dominant phase...

The fluidal behavior of pyroclastic flows is commonly attributed to high gas pore pressures and associated fluidization effects. We carried out experiments on fluidized volcanic ash at 170°C, which hot enough reduce cohesive effects moisture. were generated in a 3‐m‐long, horizontal lock‐exchange flume. was expanded uniformly the flume reservoir by up 43% above loose packing then released. Each flow defluidized progressively down until motion ceased. Initial expansion E initial height h 0...

In this study, we propose a particle sedimentation/aggradation law for homogeneous concentrated suspensions. This law, valid in the Stokes flow regime, can be used to describe sedimentation process observed short-lived rapid flows, developed at high Reynolds numbers, that described as low-viscosity quasi-parallel flows traveling constant velocity and progressively sediment during dominant phase of transport leave triangular or trapezoidal deposit slope. The aggradation thus predicted from...

In this paper, we used a three-dimensional discrete-grain model (Grains3D) to explore the flow and deposit characteristics of unchannelized dam-break collapses. A series numerical experiments was performed predict behaviour different granular columns (characterized by initial aspect ratio a, varying from 0.5 18). As observed previously in similar channelized flows axisymmetric slumps, phenomenology collapse depends strongly on revealing regimes. Small collapsing heaps (a ≲ 3) develop shallow...

This work focuses on the mechanisms that trigger internal erosion of pervious foundation flood protection dikes. The origin these permeable layers is generally attributed to presence a paleo-valley and paleo-channels filled with gravelly-sandy sediments beneath river bed These may extend into protected area. Visual observations leaks, sand boils sinkholes in area testify processes underground soil. Local geological conditions are part information be sought explain processes: soils position...

The study of internal erosion earth dams, dikes, and levees is an essential ingredient to address their safety. Indeed, known be a major cause failure for dams levees. Several sections the Agly river dike (south-west France) are affected by appearance sand boils on side protected zone. These phenomena generally occur without any significant itself. In order better understand reasons these phenomena, we took advantage drought (dry riverbed) image, using induced polarization tomography,...

Observations of the settling velocity suspensions irregular particles are found to depend on (i) difference density between and suspension (ii) a viscosity which depends ratio concentration loose packing concentration.

This paper develops a physical model able to describe the dam-break flow of particulate suspensions that sediment progressively during propagation at constant velocity solely depends on mixture properties. The considers suspension as an equivalent fluid density and negligible viscosity leads good prediction duration deposits shape. These findings allow formulation consistent shallow-water equations can be used compute dense basal layer small-volume pyroclastic flows.

Hydrodynamic dispersion is a crucial mechanism for modelling contaminant transport in subsurface engineering and water resources management whose determination remains challenging. We use Digital Rock Physics (DRP) to evaluate the longitudinal of sandpack. From three-dimensional image porous sample obtained with X-ray microtomography, we method volume averaging assess dispersion. Our numerical implementation open-source relies on modern scientific platform that allows large computational...

Abstract The aim of this paper is to evaluate the vulnerabilityafter point source contamination and characterizewater circulations in volcanic flows located theArgnat basin system (Chaîne des Puys, FrenchMassif Central) using a tracer test performed by injectinga iodide solution. analysis breakthrough curves allowedthe hydrodispersive characteristics massivelava be determined. Large Peclet numbers indicateda dominant advective transport. multimodal featureof combined with high valuesof mean...

Ce travail porte sur les mécanismes physiques à l’origine des processus d’érosion interne dans sols de fondation digues protection contre inondations. La présence matériaux perméables est le plus souvent associée la d’une paléo-vallée comblée sédiments alluviaux sous lit rivière et ou paléo-chenaux sableux pouvant s’étendre au niveau zone protégée. Le cas l’Agly montre que plusieurs doivent être pris en compte pour décrire ces phénomènes : l’érosion régressive, contact suffusion....

We introduce a system of Saint-Venant-type equations to model laboratory experiments dam-break particle-laden flows. explore homogeneous and non-cohesive liquid-solid suspensions monodispersed glass beads that propagate as single-phase flows, forming progressively growing deposit particles at the bottom smooth channel creating thin layer pure liquid surface. The novelty this is twofold. First, we fully characterize first-order behavior these flows (mean velocity, runout distances deposits...

The investigation of the fall a sphere at finite Reynolds number in concentrated suspension small fluidized particles leads to unexpected results regarding drag force exerted by on moving object. These results, which seem be associated with slip velocity near surface sphere, call into question interpretation effective rheology suspensions.