Spectral analysis of unsteady flow simulation in a small VAWT

The vertical axis wind turbine studied in this paper combine two rotations: one rotating movement of each blade around its own axis and one rotating movement around turbine’s axis. The aim of this paper is to analyse the effect of this two combine movements on fields of pressure and on global forces on each blade with time. Preliminary calculations showed, for some initial blade stagger angles (angle between blade 1 and x axis), that flow is highly unsteady and sometimes hardly periodic. The main goal here is to present spectral analysis of unsteady results like temporal pressure on specific points in the domain and temporal forces on blades and to show the influence of the two combine movements for two different blade stagger angles for elliptic blades

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Carte blanche concernant la vision globale de l'environnement terrestre et son évolution

A Convex-Analysis Perspective on Disjunctive Cuts

An updated version of this paper has appeared in Math. Program., Ser. A 106, pp 567-586 (2006), DOI 10.1007/s10107-005-0670-8We treat the general problem of cutting planes with tools from convex analysis. We emphasize the case of disjunctive polyhedra and the generation of facets. We conclude with some considerations on the design of disjunctive cut generators

Theoretical model for diffuse optical wave scattering from a three-dimensional slab bounded by randomly rough surfaces

7 pages, 2 figures. Contribution to the 23rd International Review of Progress in Applied Computational Electromagnetics (ACES 2007) March 19-23, 2007 Verona, Italy.Our purpose is to show how light can interact with slab bounded by rough surfaces. In this paper, we consider three-dimensional structures bounded by two-dimensional weakly rough surfaces or by two-dimensional randomly rough surfaces with small-slope. We discuss the extension of the small-slope approximation method to slabs with two randomly rough surfaces. The fourth order terms of the perturbative development are required in order to take into account the interactions between the randomly rough surfaces

The small-slope approximation method applied to a three-dimensional slab with rough boundaries

75 pages, 45 figuresInternational audienceIn this paper we present new results on the small-slope approximation method. We consider different three-dimensional structures like a randomly rough surface separating two different media and a slab delimited by one or two rough surfaces. We extend the small-slope approximation to the fourth order terms of the perturbative development, and give the expression of the cross-sections for the different polarization states. Numerical examples are treated for the studied structures and a comparison with the small-perturbation is discussed

Vers une prévision climatique des types de convection : éléments de méthode

International audienceL'objectif de notre travail est de présenter une relation entre les paramètres météorologiques restitués par les modèles généraux de circulation et les types de convection. Ce papier présente une première étape où nous explicitons une méthode de suivi ainsi que la comparaison de résultats obtenus sur une période courte (trois périodes entre octobre 2013 et janvier 2014) avec les données de réanalyse

Optimal Sensors Placement to Enhance Damage Detection in Composite Plates

This paper examines an important challenge in ultrasonic structural health monitoring (SHM), which is the problem of the optimal placement of sensors in order to accurately detect and localize damages. The goal of this study is to enhance damage detection through an optimal sensor placement (OSP) algorithm. The problem is formulated as a global optimization problem, where the objective function to be maximized is evaluated by a ray tracing approach, which approximately models Lamb waves propagation. A genetic algorithm (GA) is then used to solve this optimization problem. Simulations and experiments were conducted to validate the proposed method on a carbon epoxy composite plate. Results show the effectiveness and the advantages of the proposed method as a tool for OSP with reasonable computation time.Projet AIRCELLE (EPICE/CORALIE

LES PRINCIPAUX FACTEURS DE LA RELATION NEBULOSITE - PRECIPITATIONS SOUS LES BASSES LATITUDES : ROLE DU RELIEF ET DE LA TEMPERATURE DE LA TROPOPAUSE

International audienceL'objectif de cet article est d'évaluer à partir des longues séries de données TRMM, l'impact des effets locaux sur l'efficacité des nuages en termes de précipitation. Deux échelles très différenciées sont mises en évidence. A l'échelle locale, le relief est le facteur prédominant, alors qu'à l'échelle continentale, la température de tropopause est le facteur le plus important