Une opération de réactivation de l'économie en milieu rural

La perspectiva de desarrollo del turismo rural en Iparralde se ve como una necesidad. Para realizar este proyecto se ha creado una agrupación que reúne a todos los sindicatos, paralelamente una asociación que reúne a todas las instituciones que conciernen, también se ha creado. La Asociación de Alojamiento Rural se encarga de promover productos de calidad y hacer sobresalir las particularidades de Iparrald

Effect of vortex generator on the boundary layer detachment on NACA0015 2D foil

Control of detachment of the boundary layer around a foil found many applications in various configurations for aircraft the ability to suppress or delay the separation phenomenon leads to enhanced levels of lift, reduce noise and drag. Many studies have been experimentally conducted to test the effectiveness of different actuators. For example, regarding the methods called "active" which introduce external energy into the fluid, it distinguishes the use of movable walls Modi et al. [1], methods based on suction or blowing Wygnanski [2], McCormick [3], acoustic methods Collins [4], thermal Chang [5] or electromagnetic Gad-el-Hak [6]. In recent years, synthetic jets have been used to control flow separation and to stabilize the boundary layer by adding/removing momentum with the formation of vortical structures Wygnanski [7]. More recently, Gilarranz et al. [8] performed a study of flow separation over NACA0015 airfoil with synthetic jets control, but the modification by the control of the boundary layer has not been clearly identify

Investigation of the flow inside an urban canopy immersed into an atmospheric boundary layer using laser Doppler anemometry

Laser Doppler anemometry (LDA) is used to investigate the flow inside an idealized urban canopy consisting of a staggered array of cubes with a 25% density immersed into an atmospheric boundary layer with a Reynolds number of δ+=32,300. The boundary layer thickness to cube height ratio (δ/h=22.7) is large enough to be representative of atmospheric surface layer in neutral conditions. The LDA measurements give access to pointwise time-resolved data at several positions inside the canopy (z=h/4, h/2, and h). Synchronized hot-wire measurements above the canopy (inertial region and roughness sublayer) are also realized to get access to interactions between the different flow regions. The wall-normal mean velocity profile and Reynolds stresses show a good agreement with available data in the literature, although some differences are observed on the standard deviation of the spanwise component. A detailed spectral and integral time scale analysis inside the canopy is then carried out. No clear footprint of a periodic vortex shedding on the sides of the cubes could be identified on the power spectra, owing to the multiple cube-to-cube interactions occuring within a canopy with a building density in the wake interference regime. Results also suggest that interactions between the most energetics scales of the boundary layer and those related to the cube canopy take place, leading to a broadening of the energy peak in the spectra within the canopy. This is confirmed by the analysis of coherence results between the flow inside and above the canopy. It is shown that linear interactions mechanisms are significant, but reduced compared to smooth-wall boundary-layer flow. To our knowledge, this is the first time such results are shown on the dynamics of the flow inside an urban canopy

Application of Laser Doppler Anemometry to estimate turbulent power spectra inside an urban canopy

International audienceIn the present contribution, we propose to make use of Laser Doppler Anemometry to investigate the dynamics of the flow inside an urban canopy immersed into a thick turbulent boundary layer. Previous studies dedicated to such flows (Castro et al. 2006; Reynolds and Castro 2008) have focused the core of their analysis on the roughness sublayer region or on the inertial region. In contrast, the region below the canopy interface have received little attention so far, and only mean velocity or Reynolds stresses data can be found in the literature. Indeed, getting access to the dynamics of the flow inside the canopy represents a real experimental challenge: the flow is turbulent, 3-dimensionnal, and due to the tight clearance, only non-intrusive laser-based techniques such as LDA or PIV can be used. In this contribution, for the first time, a spectral analysis of the flow is carried out inside the canopy region. This is made possible thanks to very thorough LDA measurements as well as the use of advanced post-processing algorithm to compute temporal power spectra. Indeed, LDA measurement yields non-equidistantly spaced data points, and standard FFT algorithms cannot be used. A detailed comparison of various algorithms is undertaken, and a slight improvement is proposed to reduce the impact of measurement noise. Finally, the power spectra inside the canopy are analyzed and the main implications on the flow dynamics are discussed

Contrôle d'écoulement en Aérodynamique automobile

Nous présentons ici une rapide revue des études que nous avons réalisées sur le thème du contrôle d'écoulement appliqué à l'Aérodynamique Automobile. Nous présentons plusieurs exemples de techniques de contrôle d'écoulement mises en oeuvre sur des formes simplifiées de véhicules (corps de Ahmed) ainsi que sur des véhicules séries et des concept-cars

Application of Laser Doppler Anemometry to estimate turbulent power spectra inside an urban canopy

In the present contribution, we propose to make use of Laser Doppler Anemometry to investigate the dynamics of the flow inside an urban canopy immersed into a thick turbulent boundary layer. Previous studies dedicated to such flows (Castro et al. 2006; Reynolds and Castro 2008) have focused the core of their analysis on the roughness sublayer region or on the inertial region. In contrast, the region below the canopy interface have received little attention so far, and only mean velocity or Reynolds stresses data can be found in the literature. Indeed, getting access to the dynamics of the flow inside the canopy represents a real experimental challenge: the flow is turbulent, 3-dimensionnal, and due to the tight clearance, only non-intrusive laser-based techniques such as LDA or PIV can be used. In this contribution, for the first time, a spectral analysis of the flow is carried out inside the canopy region. This is made possible thanks to very thorough LDA measurements as well as the use of advanced post-processing algorithm to compute temporal power spectra. Indeed, LDA measurement yields non-equidistantly spaced data points, and standard FFT algorithms cannot be used. A detailed comparison of various algorithms is undertaken, and a slight improvement is proposed to reduce the impact of measurement noise. Finally, the power spectra inside the canopy are analyzed and the main implications on the flow dynamics are discussed

Innovative embedded sensors for power electronic modules: CAPTIF – ANR research project

Innovative embedded sensors for power electronic modules: CAPTIF – ANR research projec

Embedded set of sensors for power electronic modules

This study deals with the challenges for driving Wide Band Gap modules to maturity. In this study, development, integration and signal processing techniques of several types of sensors are studied. Industrial and academic partners, within CAPTIF project, are proposing complementary skills and experiences in the technological and scientific domains: multi-physic sensors, signal processing, integration and reliability for power electronics. Nanoparticle-based strain gauges, temperature sensors and electromagnetic array sensors will be validated and integrated in power an electronic power module. A specific multi-physic model will be developed in order to specify the best location of interest within the power module. These features will result in a better knowledge of real-time current density location, as well as current frequencies. For both sensor types, the data packaging will be challenging spin-offs. Finally, advanced data processing techniques – estimation as well as signal processing – will be adapted to numerous sensor outputs. A clean room process flowchart will be established to guarantee an advanced pre-industrial prototyping

Conception de capteurs intégrés et logiciels pour des modules d'électronique de puissance

Conception de capteurs intégrés et logiciels pour des modules d'électronique de puissanc

Recherches sur l'usure dentaire et évaluation "in vitro" de biomatériaux restaurateurs avec le simulateur d'usure UVSB2

L'usure dentaire bien que largement étudiée en anthropologie et en odontologie reste peu prise en compte dans le choix des biomatériaux restaurateurs des faces occlusales. Les deux premiers chapitres constituent une revue de littérature sur la tribologie, les classifications de l'usure dentaire et les mécanismes d'usure des céramiques dentaires et des composites avec l'émail. Sur le plan de la recherche nous avons mis au point l'UVSB2 qui est un simulateur d'usure de type "pin or plate", avec lequel nous réalisons des tests d'usure "in vitro" à deux corps, en eau ditillée, et des tests d'usure à trois corps, en résine poly-métacrylate de méthyl. Le troisième chapitre fait la synthèse des principaux simulateurs d'usure existant, puis présente l'usuromètre UVSB2. Nous exposons dans le quatrième chapitre l'étude comparative de la résistance à l'usure d'un ensemble de composites micro-hybrides et de céramiques dentaires, entre eux et par rapport à des matériaux de référence comme l'émail, la dentine et l'amalgame d'argent. Les rayures obtenues par le passage répété d'un "indenteur" en alumine, sous une charge constante, sont mesurées en profilométrie mécanique et statistiquement analysées. La plupart des céramiques et des composites micro-hybrides testés ont des taux d'usure significativement inférieurs à ceux de l'émail. L'usure est nettement plus forte en eau distillée, où l'attrition domine, qu'en milieu de résine PMMA, où le troisième corps absorbe les contraintes. Dans les conditions de l'expérimentation, les taux d'usure les plus faibles sont obtenus dans les deux milieux testés, pour des composites micro-hybrides de laboratoires, ce qui est prometteur pour leur usage prothétique. Sur le plan clinique la finalité est de mieux adapter les coefficients d'usure des biomatériaux de reconstruction à l'usure physiologique de l'émail pour s'intégrer dans le vieillissement harmonieux de l'appareil manducateur.The dental wear has been largely studied in anthropology and odontology nevertheless it get poor consideration in the choice of restoration materials for occlusal tables. Chapters one and two constitute a review of literature of tribology, dental wear classifications and wear mechanisms of dental ceramics and composites with enamel. In our research we develop the UVSB2 "pin or plate" oral wear simulator which permit to realise "in vitro" two bodies wear tests, in distilled water, and three bodies wear tests, in a food like slurry of poly methyl metacrylate resin (PMMA) and water. Third chapter is a bibliographical review of the principal wear simulators, and describe the UVSB2 machine. In fourth chapter we expose a comparative study of wear resistance of several microhybrid composites and dental ceramics. Their are compared between them and with reference materials like enamel, dentine and amalgam. Stripes are obtained by a sliding motion on samples of an alumina "indentor", under a constant load, and are measured in mechanical profilometry and statistically analyzed. The results of this investigation indicate that most ceramics and microhybrid composites tested have wear rates significantly lower than those of enamel in the two environments. Wear is definitely stronger in distilled water, where attrition mecanism dominate, that in PMMA resin environment, where constraints are absorbed by the third body. Under our experimental conditions, lowest wear rates are obtained in the two environments, for laboratories microhybrid composites which promise a great prosthetic development. In clinical practice the finality is a better adaptation of the wear coefficients of prostodontic materials with enamel physiological wear. We expect an harmonious integration in oral ageing.BORDEAUX2-BU Sci.Homme/Odontol. (330632102) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF