Pascal Dupont

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We investigated via wind-tunnel experiments the role of the boundary conditions at the bed in the aeolian sand transport. We analyzed two different bed configurations: one with a sandy erodible bed and the other with a non-erodible bed. By using Particle Tracking Velocimetry technique (PTV), we characterized the saltation layer in both configurations and(More)
We report on wind-tunnel measurements of particle velocity distribution in aeolian transport. By performing extended statistics, we show that for saltation occurring over an erodible bed the vertical lift-off velocity distributions deviate significantly from a Gaussian law and exhibit a long tail accurately described by a lognormal law. In contrast,(More)
We present stratigraphic measurements of humidity and bulk density beneath the surface of a barchan dune obtained with a capacitance probe. A model shows that air seeping through the sand bed in response to spatial variations of static pressure along the ripple surface guides water vapor through ripple crests and gradually stores dust beneath troughs. The(More)
Measurements indicate that the solid volume fraction on a sand ripple varies from random jammed packing at troughs to the minimum stable packing at crests. By relating variations of the solid volume fraction to those of the surface turbulent shear stress, a collisional model of reptation suggests a qualitative origin for these observations. Although the(More)
Complex matter may take various forms from granular matter, soft matter, fluid-fluid, or solid-fluid mixtures to compact heterogeneous material. Cellular automata models make a suitable and powerful tool for catching the influence of the microscopic scale in the macroscopic behavior of these complex systems. Rather than a survey, this paper attempts to(More)
In order to have a better knowledge on the behaviour of the lumbar spine, we investigated the response under loads (flexion, extension, lateral bending and torsion) of a finite element model (L3-L5 segment) submitted to changes of parameters (disc height, nucleus Poisson coefficient, posterior disc fibres, facet orientation and asymmetry and gap). These(More)
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