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Nantes, France

École Centrale de Nantes is a renowned French Grande école of engineering, established in 1919 under the name of Institut Polytechnique de l'Ouest.École Centrale de Nantes is one of the Centrale Graduate Schools associated as the Groupe Centrale network with its sister institutions . A member of the TIME network, that enables student exchanges among leading European engineering schools, it is also a founder of the France AEROTECH association of French engineering schools. Wikipedia.

In this paper, wave farms composed of two either surging or heaving wave energy converters are considered. Using a numerical model which takes into account wave interactions, the impact on the absorbed wave power of the separating distance between the two systems and the wave direction is studied. In regular waves, a modified qmod factor is introduced and it is found to be more relevant than the usual q factor for identifying this impact. Then, it is shown that, asymptotically, the alteration of the energy absorption due to wave interaction effects decreases with the square root of the distance. This is a slow decay, which leads to a still significant modification of the wave energy absorption at long distance (up to 15% at a distance of 2000 m). In irregular waves, it is shown that constructive and destructive effects compensate each other, particularly when considering the mean annual power. It leads to a smaller impact of the wave interactions on the absorbed energy and shorter distances (smaller than 10% for distances greater than 400 m). Finally, conclusions on if wave interactions should be taken into account or not when designing a wave farm are drawn in function of the distance. © 2010 Elsevier Ltd. All rights reserved. Source

Capdeville G.,Ecole Centrale Nantes
Journal of Computational Physics | Year: 2011

This article presents a numerical model that enables to solve on unstructured triangular meshes and with a high-order of accuracy, a multi-dimensional Riemann problem that appears when solving hyperbolic problems. For this purpose, we use a MUSCL-like procedure in a " cell-vertex" finite-volume framework. In the first part of this procedure, we devise a four-state bi-dimensional HLL solver (HLL-2D). This solver is based upon the Riemann problem generated at the centre of gravity of a triangular cell, from surrounding cell-averages. A new three-wave model makes it possible to solve this problem, approximately. A first-order version of the bi-dimensional Riemann solver is then generated for discretizing the full compressible Euler equations. In the second part of the MUSCL procedure, we develop a polynomial reconstruction that uses all the surrounding numerical data of a given point, to give at best third-order accuracy. The resulting over determined system is solved by using a least-square methodology. To enforce monotonicity conditions into the polynomial interpolation, we develop a simplified central WENO (CWENO) procedure. Numerical tests and comparisons with competing numerical methods enable to identify the salient features of the whole model. © 2011 Elsevier Inc. Source

Chinesta F.,Ecole Centrale Nantes
Archives of Computational Methods in Engineering | Year: 2013

This paper proposes a first attempt to define a two-scales kinetic theory description of suspensions involving short fibers, nano-fibers or nanotubes. We start revisiting the description of dilute enough suspensions for which microscopic, mesoscopic and macroscopic descriptions are available and all them have been successfully applied for describing the rheology of such suspensions. When the suspensions become too concentrated fiber-fiber interactions cannot be neglected and then classical dilute theories fail for describing the rich microstructure evolution. In the semi-concentrated regime some interaction mechanisms that mimetic the randomizing effect of fiber-fiber interactions were successfully introduced. Finally, when the concentration becomes high enough, richer microstructures can be observed. They involve a diversity of fiber clusters or aggregates with complex kinematics, and different sizes and shapes. These clusters can interact to create larger clusters and also break because the flow induced hydrodynamic forces. In this paper we propose a double-scale kinetic theory model that at the first scale consider the kinematics of the clusters, whose structure itself is described at the finest scale, the one related to the rods constituting the clusters. © 2013 CIMNE, Barcelona, Spain. Source

Agency: Cordis | Branch: H2020 | Program: RIA | Phase: MG-1.9-2015 | Award Amount: 1.40M | Year: 2016

This research project focuses on several key Direct Energy Deposition (DED) Additive Manufacturing (AM) processes that have great potential to be used as cost-effective and efficient repairing and re-manufacturing processes for aerospace components such as turbine blades and landing gears. This project aims to conduct fundamental research to understand the material integrity through chosen DED AM processes, the accuracy and limitations of these deposition processes, effective defect geometry mapping and generation methods, and automated and hybrid DED and post-deposition machining strategies. This project intends to connect repair and re-manufacturing strategies with design through accurate DED process simulation and novel multi-disciplinary design optimisation (MDO) methods to ultimately reduce the weakness of aerospace component at design stage and prolong their the lifecycles. Both powder-based and wire-based DED systems will be investigated to establish an across-the-board comparative study. The data collected through this comprehensive comparative study will be extremely valuable for the OEMs of this project (i.e. GKN, PWC, and HDI) to understand the pros and cons of these DED systems and will help them to select suitable repair and re-manufacturing strategies. The tests conducted in this research are also extremely beneficial for the SMEs in this project (i.e. Liburdi, AV&R, DPS) to validate their existing repairing systems and techniques.

École Centrale Nantes and Center Nationale Of La Recherche Scientique | Date: 2012-11-06

A method for a real-time dynamic simulation of a response of a complex system or process controlled by a plurality of driving factors P

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