Éditeur(s) : HAL CCSD
Résumé : National audience
Des expériences dans un bassin de 30 m x 30 m ont été réalisées dans l'objectif de caractériser la dynamique d'un courant d'arrachement et les évolutions morphologiques associées. La plage de sable fin (diamètre médian 166 microns) couvrait la largeur du bassin (30 m en longshore ) pour un profil total de 20 m cross-shore . La formation de courants sagittaux a été forcée par une houle frontale (spectre de Jonswap) avec un déficit d'énergie au centre du bassin. Une séquence accrétive complète de plage intermédiaire à simple barre (selon classification de WRIGHT & SHORT, 1984) a été reproduite. La barre s'est progressivement tridimensionnalisée en forme de croissant puis s'est connectée au haut de plage avec la présence de deux chenaux profonds qui se sont ensuite comblés pour obtenir une plage à terrasse au bout de plusieurs dizaines d'heures. L'association des mesures hydrodynamiques et morphodynamiques montre que le comblement des chenaux est alimenté par le haut de plage.
XI èmes Journées Nationales Génie Côtier - Génie Civil
Sables d'Olonne, France

hal-00861953
https://hal.archives-ouvertes.fr/hal-00861953

Éditeur(s) : HAL CCSD
Résumé : International audience
Some research on written production has focused on the role of the syllable as a processing unit. However, the precise nature of this syllable unit has yet to be elucidated. The present study examined whether the nature of this processing unit is orthographic (i.e., the ortho-syllable) or phonological. Thirty-two native French speakers were asked to copy adjectives on a digitizer, successively adding a plural and a feminine one-letter morpheme to the same adjective. The adjective agreement could modify the structure of both phonological and orthographic syllables, only ortho-syllabic structure, or leave both unchanged. When the change modified only the orthographic syllable structure, there was an increase in duration at the letter before the syllable boundary. By contrast, when adding a letter changed both orthographic and phonological structures, an increase in the duration of the inter-letter interval was observed. Importantly, the increase in duration cannot be explained exclusively by the addition of a letter because the addition of a plural inflection did not significantly influence the dynamics of handwritten production. These results are consistent with the idea that ortho-syllables serve as a processing unit during handwriting, and that this type of syllable is specific to the written code.
17th Biennial Conference of the International Graphonomics Society
Pointe-à-Pitre, Guadeloupe

hal-01165879
https://hal.univ-antilles.fr/hal-01165879
https://hal.univ-antilles.fr/hal-01165879/document
https://hal.univ-antilles.fr/hal-01165879/file/IGS_2015_submission_14.pdf

Éditeur(s) : HAL CCSD Météo et Climat
Résumé : International audience
D'initiative française, le projet international HyMeX a pour objectif d'améliorer la compréhension du cycle de l'eau en Méditerranée, de sa variabilité, de l'échelle de l'événement météorologique aux échelles saisonnières et interannuelles, et de ses caractéristiques sur une décennie, dans un contexte de changement global. Le projet est motivé par le rôle déterminant des processus de mésoéchelle, couplés entre l'atmosphère, la mer et la terre, sur la variabilité du système climatique et sur le déclenchement d'événements hydrométéorologiques extrêmes (précipitations et inondations, vents forts et convection océanique, canicules et sécheresses). Le projet vise enfin à évaluer les conséquences de ces événements extrêmes sur la vulnérabilité sociale et économique de cette région et sa capacité d'adaptation.
ISSN: 0026-1181

hal-00828758
https://hal.archives-ouvertes.fr/hal-00828758
https://hal.archives-ouvertes.fr/hal-00828758/document
https://hal.archives-ouvertes.fr/hal-00828758/file/meteo_2013_80_23%20%281%29.pdf
DOI : 10.4267/2042/48792

Éditeur(s) : HAL CCSD Météo et Climat
Résumé : International audience
Les risques hydrométéorologiques sont au coeur du programme de recherche HyMeX sur le cycle de l'eau en Méditerranée. HyMeX a pour ambition d'améliorer leur prévision, de mieux connaître leur variabilité à l'échelle pluriannuelle et de renseigner sur leur évolution, dans le contexte du changement climatique. À cette fin, deux campagnes de mesures dédiées à ces événements extrêmes (SOP1 : pluies intenses et crues rapides ; SOP2 : vents forts et formation d'eaux denses) sont organisées en Méditerranée nord-occidentale, entre septembre 2012 et mars 2013.
ISSN: 0026-1181

hal-00829760
https://hal.archives-ouvertes.fr/hal-00829760
DOI : 10.4267/2042/48793

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
This study describes a laboratory experiment on rip current circulations over a moveable bed. Rip current characteristics over eight contrasting nature-like beach morphologies are investigated. The seabed varied from reasonably alongshore uniform to strongly alongshore nonuniform with crescentic patterns and bar-rip morphologies, representative of a full morphological down-state sequence. The same offshore shore-normal waves were generated by the wavemaker for the eight situations with the same mean water level to study the sensitivity of rip current characteristics as a function of the beach morphology only. In each case, a 30 to 60 min video run was used to track a large number of drifters released within the surf zone. Results show the presence of classic rip current patterns with counterrotating cells and a relatively narrow offshore-directed jet varying from shore-normal to strongly skewed. Wave-driven circulations were strongly unstable. Computed standard deviations of flow intensity and direction provide high-resolution information on the spatial variability of rip current instabilities. Highly pulsating and weakly directionally variable offshore-directed flow is observed in the rip neck for well-developed bar-rip morphologies that turns into a weakly pulsating and highly directional variable rip current flow with decreasing beach alongshore nonuniformity. Proposing a definition of rip current intensity based on the rip current circulation geometry, rip current intensity was found to linearly increase with increasing measure of beach alongshore nonuniformity within both the low-energy and moderate-energy rip current regimes. To date, our laboratory experiment provides the first extensive quantitative rip current information during a full down-state sequence for a given wave condition.
ISSN: 0148-0227

hal-00602920
https://hal.archives-ouvertes.fr/hal-00602920
DOI : 10.1029/2010JC006343

Éditeur(s) : HAL CCSD World Scientific
Résumé : The present paper presents a laboratory experiment of rip current circulations over a moveable bed. The rip current characteristics over four distinct beach morphologies, exhibiting more or less developed nature-like bar-rip morphology,were investigated. For each video run, the same off shore shore-normal waves were generated by the wave maker with the same mean water level in order to study the sensitivity of the rip current characteristics as a function of the beach morphology only. In each case, a 1-hour video run was used to track a large number (~30) of drifters released within the surf zone. Image coordinates were then rectifie d to still water level Cartesian coordinates to compute drifter velocities, mean characteristics and surf zone rete ntion rates. Results show the presence of classic rip current patterns with counter-rotating cells and a relatively narrowoffshore-directed jet with, for three of the situations, a reasonably symmetric shape. Non-surprisingly, it was found that rip current intensity increases with increasing relative depth of the rip channel. The wave-driven circulations were strongly unstable. Computed standard deviation in fl ow intensity and direction provides high resolution information on the spatial variability of the rip current insta bilities with, for instance, highly-pulsating and weakly directionally variable offshore-directed flow in the rip channel. Conversely to what was previously hypothesized in the literature, there was hardly trace of vortices being shed offs hore and drifters exiting the surf zone compartment were not systematically caught by a pulsating jet. The cause for drifter exiting the semi-enclosed surf zone compartment remains, however, elusive and deserves further investigations. The computed surf zone retention rates (~90%) were of the order of those previously observed in the field, with no clear relationship with the mean rip current velocity or relative depth of the rip channel. Further video-runs will have to be analyzed to explore potential explanations
Proceedings of Coastal Dynamics 2009 Impacts of Human Activities on Dynamic Coastal Processes

ISBN : 978-981-4282-46
hal-00854534
https://hal.archives-ouvertes.fr/hal-00854534