Archive Institutionnelle de l'Ifremer

Nouveaux documents

Ref.° 1-30 / 30 1 2 3

Allen Arthur, Roth Jens-Christian, Maisondieu Christophe, Breivik Oyvind, Forest Bertrand
The leeway (windage) of five typical SAR/HAZMAT objects (person in water, mine, small sailboat, small open boat and a 20-ft container) and is studied. The method is applicable to objects smaller than 30m
2010-08-27.   Rapport
Nogues Loic, Gangnery Aline
Depuis 1989, des évaluations de stocks des bivalves en élevage conduites par l’Ifremer sont réalisées tous les 5 ans sur l’ensemble des bassins conchylicoles de Normandie. Dans le cadre du projet OGIVE et du développement d’outils de gestion des zones de production, une nouvelle évaluation des stocks de moules en élevage s’est déroulée en 2006. L’application de stratégies d’échantillonnage, adaptées (échantillonnage stratifié, à deux degrés ou aléatoire simple) à chacun des grands secteurs [...]
2008-09.   Rapport scientifique
L’objectif général du projet OGIVE est d’acquérir des connaissances sur le fonctionnement des écosystèmes conchylicoles de Basse-Normandie dans le but d’établir une plateforme de données communes à l’ensemble des partenaires du projet. Ces connaissances sont ensuite utilisées pour développer des outils novateurs permettant de fournir des avis et expertises aux gestionnaires du Domaine Public Maritime. Le projet a ainsi pour objectif de contribuer au développement durable de la filière [...]
2008-03.   Rapport scientifique
Marie Louis, Daviaud F
We report measurements linking velocity fluctuations with the turbulent drag in a turbulent closed flow, namely the von Karman flow. Making use of the angular momentum balance equation in integral form, we obtain a simple expression for the torque applied by the forcing mechanism, which we check against quantitative laser Doppler velocimetry measurements. We then decompose the angular momentum flux into contributions coming from the different spectral components of the flow. We provide evidence [...]
2004-02.   Physics Of Fluids
Marie Louis, Normand C, Daviaud F
We investigate dynamo action by solving the kinematic dynamo problem for velocity fields of the von Karman type between two coaxial counter-rotating propellers in a cylinder. A Galerkin method is implemented that takes advantage of the symmetries of the flow and their subsequent influence on the nature of the magnetic field at the dynamo threshold. Distinct modes of instability have been identified that differ by their spatial and temporal behaviors. Our calculations give the result that a [...]
2006-01.   Physics Of Fluids
Monchaux R., Berhanu M., Bourgoin M., Moulin M., Odier Ph., Pinton J. -F., Volk R., Fauve S., Mordant N., Petrelis F., Chiffaudel A., Daviaud F., Dubrulle B., Gasquet C., Marie Louis, Ravelet F.
We report the observation of dynamo action in the von Karman sodium experiment, i.e., the generation of a magnetic field by a strongly turbulent swirling flow of liquid sodium. Both mean and fluctuating parts of the field are studied. The dynamo threshold corresponds to a magnetic Reynolds number R-m similar to 30. A mean magnetic field of the order of 40 G is observed 30% above threshold at the flow lateral boundary. The rms fluctuations are larger than the corresponding mean value for two of [...]
2007-01.   Physical Review Letters
Dubrulle B, Marie Louis, Normand C, Richard D, Hersant F, Zahn Jp
We discuss the possibility that astrophysical accretion disks are dynamically unstable to non-axisymmetric disturbances with characteristic scales much smaller than the vertical scale height. The instability is studied using three methods: one based on the energy integral, which allows the determination of a sufficient condition of stability, one using a WKB approach, which allows the determination of the necessary and sufficient condition for instability and a last one by numerical solution. [...]
2005-01.   Astronomy & Astrophysics
The maritime economy includes the activities linked to the sea, namely: - Marine resource extraction: living resources and marine minerals, - Exploitation of marine space and of physical properties of marine waters (energy plants - using marine water as a heat sink, marine renewable energies, submarine cable laying, - maritime and coastal construction and public works, maritime transport, Navy), - Exploitation of seascapes (tourism, leisure, boating), - Resource processing (of living resources [...]
2014-10.   Rapport
Cury Philippe M., Fromentin Jean-Marc, Figuet Sarah, Bonhommeau Sylvain
The relationship between spawning fish abundance and the number of offspring, the so-called stock-recruitment relationship, is crucial for fisheries management and conservation measures. Using the most comprehensive data set ever assembled, we quantify this relationship for 211 fish stocks worldwide, revealing a global pattern with a pervasive asymptotic shape that shows increasing recruitment reaching an upper limit for values around half to two-thirds of parental biomass. This corroborates [...]
2014-12.   Oceanography
Salton Marcus, Saraux Claire, Dann Peter, Chiaradia André
Using body mass and breeding data of individual penguins collected continuously over 7 years (2002–2008), we examined carry-over effects of winter body mass on timing of laying and breeding success in a resident seabird, the little penguin (Eudyptula minor). The austral winter month of July consistently had the lowest rate of colony attendance, which confirmed our expectation that penguins work hard to find resources at this time between breeding seasons. Contrary to our expectation, body mass [...]
2015-01.   Royal Society Open Science
1 2 3