Evaluation des paramètres de viscosité interne et de frottement pour les avalanches, afin de pouvoir représenter numériquement leur écoulement. Définition des fourchettes pour ces paramètres selon que la neige se déplace sur de la neige ou sur la
Rotating fluids in geophysics and planetary physics
Cosmos ; Fluide géophysique ; Fluides en rotation ; Flux géostrophique ; Flux magnétostrophique ; Force de Coriolis ; Gphy ; Géographie physique ; Géophysique ; Planétologie ; Rotation de la Terre
The paper is about fluid motions that are strongly influenced by Coriolis forces. It outlines a variety of experimental and theoretical studies of basic hydrodynamic and magnetohydrodynamic processes in rotating fluids and mentions various
Un modèle digital bidimensionnel de mécanique desfluides a été adapté à la modélisation des parcours d'avalanches. Il permet de distinguer les effets de la géométrie du couloir de ceux des facteurs d'écoulement, tels que frottement et rugosité. Le
profil longitudinal du couloir est discrétisé en sections de 10-20 m. Le programme permet de calculer pour chaque section la vitesse moyenne d'avalanche, l'emplacement et le volume du culot d'avalanche. L'algorithme du programme est performant. Le
programme permet une simulation précise de l'écoulement des avalanches. Problèmes des conditions initiales et des valeurs paramétriques nécessaires au calage du modèle, dans les conditions les plus variées.
This paper addresses the recent trend in fluvial geomorphology towards using computational fluiddynamics to explore the adjustment between flow processes, sediment transport and river channel morphology. It aims to evaluate the extent to which 3D
Climatologie ; Dynamique de l'atmosphère ; El Niño ; Interaction océan-atmosphère ; Mécanique desfluides ; Océan ; Onde planétaire ; Oscillation nord-atlantique ; Perturbation atmosphérique ; Propagation des ondes ; Stratification des eaux
Atmospheric disturbance ; Atmospheric dynamics ; Climatology ; El Niño ; North Atlantic oscillation ; Ocean ; Ocean atmosphere interaction ; Planetary wave ; Water stratification ; Wave propagation
Climatología ; Dinámica de la atmosfera ; Estratificación de las aguas ; Interaccíon océano-atmósfera ; Océano ; Onda planetaria ; Perturbación atmosférica
Cours destiné aux étudiants de 2ème cycle de l'Ecole Polytechnique, très axé sur la mécanique desfluides et à forte connotation mathématique. - (FC)
A computational fluiddynamics (CFD) model is used to simulate a stable wind blowing over slope beds of varying height and coupled with the slope-compensating fluid threshold friction velocity formula. Based on the CFD-based model, quantitative
Fluid speed variability and the importance to managing fish habitat in rivers
Aménagement hydraulique ; Biogéographie ; Canada ; Capacité de charge ; Charge en suspension ; Cours d'eau ; Débit ; Ecoulement fluvial ; Habitat ; Ontario ; Poisson
An evaluation of fluid speed profiles is presented using field data collected from spawning streams in Ontario, Canada. The data have been subjected to an interpolation algorithm, minimum curvature, to deliver a more accurate view of fluid speed
patterns. The results show that fluid speed patterns vary completely within the same cross-section under different flow regimes, even when the mean depth and mean speed of the flow are virtually unchanged, and that mean speed depiction of flow is inaccurate
when considering particle transport/deposition. The minimum curvature technique of data interpolation is shown to be an accurate method for visualizing fluid speed patterns.
Dix contributions de météorologie dynamique allant de l'analyse mécanique à la modélisation numérique de l'atmosphère. La plupart des contributions ont été publiées dans la revue Weather. Cet ouvrage met à la portée des non-spécialistes tels que
géographes, climatologues et hydrologues les résultats fondamentaux actuels de la météorologie dynamique. (Cch).
Computational fluiddynamics modelling of boundary roughness in gravel-bed rivers : an investigation of the effects of random variability in bed elevation
Devon ; England ; Fluvial dynamics ; Numerical model ; Roughness ; Simulation ; Stream ; Turbulence ; United Kingdom
Results from a series of numerical simulations of two-dimensional open channel flow, conducted using the computational fluiddynamics (CFD) code FLUENT, are compared with data quantifying the mean and turbulent characteristics of open-channel flow
Representing the bed roughness of coarse-grained streams in computational fluiddynamics
Colorado ; Fluvial dynamics ; Grain size distribution ; Gravel ; Mathematical model ; Methodology ; River bed ; Roughness ; Stream ; Stream flow ; United States of America
Adequately characterizing the effects of gravel and cobble beds on flow hydraulics in computational fluiddynamics (CFD) is a difficult challenge due to the scale of roughness lengths and the inadequacy of traditional roughness representations
Electrical imaging of sliding geometry and fluids associated with a deep seated landslide (La Clapière, France)
Alpes du Sud ; Alpes-Maritimes ; Dynamique de versant ; France ; Glissement de terrain ; Géophysique ; Méthodologie ; Tomographie de résistivité électrique ; Versant
Alpes du Sud ; Alpes-Maritimes ; Electrical resistivity tomography ; France ; Geophysics ; Landslide ; Methodology ; Slope ; Slope dynamics
Alpes del Sur ; Deslizamiento deterreno ; Dinámica de vertiente ; Francia ; Geofísica ; Metodología ; Vertiente
of the landslide structure, that could be compared with 3 provided ERT profiles performed within the landslide body. Very good correlations were obtained for the determination of sub-horizontal structures and associated fluid circulations. It confirmed the position
Computational fluiddynamics as a tool for investigating separated flow in river bends
This paper illustrates, firstly, how a computational fluiddynamics (CFD) program may be used to reproduce the qualitative features of the mean flow in a real river bend to allow testing of the model's capabilities. It is then shown how the CFD code
Computational fluiddynamics and the physical modelling of an upland urban river
This paper describes the application of a commercially available, three-dimensional computational fluiddynamic (CFD) model to simulate the flow structure in an upland river that is prone to flooding. Simulations use a rectangular channel geometry
Géographie physique ; Paléoclimatologie ; Précambrien ; Rotation de la Terre
Palaeological evidence indicates that the rotation rate of the Earth during the late Precambrian was 2-2.5 times faster than now. Typically high rotation rate in a fluid system reduces the characteristic size of dynamic features, their associated
A study on fluvial dynamic geomorphology and its experiment and simulation
Channel geometry ; China ; Discharge ; Experimentation ; Fluvial dynamics ; Fluvial erosion ; Fluvial processes ; Human impact ; Model ; Simulation ; Watershed
As a branch of geomorphology, the fluvial dynamic geomorphology is a marginal science among fluiddynamics, sediment mechanics and fluvial geomorphology. With physical modelling by similarity based on Newtonian mechanics, and principle of the same
effect but different structure based on systematic theory, it is possible to study properties, formation and processes in fluvial dynamic geomorphology. A new research method, which is a combination of mathematical simulation by computer with physical
Suite de l'article dans le n3 de la même revue, pp.80-86, 4fig., bibliogr. (1réf.). Après des généralités sur le postulat de la continuité desfluides et sur les mouvements atmosphériques, l'A. définit la force de gravité, le gradient de pression et
la force de Coriolis. La seconde partie a pour objet les applications climatologiques de l'équation hydrostatique et la notion correspondante de stabilité hydrostatique. Intéressante présentation de la force géostrophique. L'article se termine sur une
étude du vent dans la couche de frottement. (JPB).
for the quantification of this pressure force which operates either on or off the bed, depending on the direction of rotation. Results from 21 near-bed sediment traps and fluid speed data at those locations show a strong relationship between variability in pressure near
and fluid-mechanics experiments may help to shed new light into geological processes whose knowledge may open new frontiers in the study of igneus systems and their evolution in time and space. - (NF)
The paper seeks to renegociate the role of visuals and visual practice within the tourist experience. The A. explores the ways in which visuals (photography) enliven tourists' becoming through a multiplicity of fluid and dynamic performances
, practices and processes. The emerging dynamics of visual practice renegociate new understandings between tourists and place to establish a series of conceptual moments.