ORBi Open Repository and Bibliography
(146.733 recursos)
In may 2007, the ULg's Administrative Board (joined in June 2007 by the FUSAGx) decided to create an institutional repository and defined a strong institutional self-archiving policy to increase the visibility, accessibility and impact of the University's publications (Board's decision).
This decision led to the official launch, in November 2008, of the ORBi platform including both the Academic Bibliography and the Institutional Repository of the Wallonia-Europe University Academy.
1.
Frequency-domain subspace identification of nonlinear mechanical systems - Noël, Jean-Philippe; Kerschen, Gaëtan
The objective of the present paper is to address the identification of a real-life strongly nonlinear space structure, the EADS-Astrium SmallSat spacecraft. To this end, a new nonlinear subspace identification method formulated in the frequency domain is exploited, referred to as the FNSI method. The frequency response functions of the underlying linear spacecraft and the amplitudes of the nonlinear internal forces are estimated based on a periodic-random data set corrupted by noise. This application is challenging for several reasons, including high modal density, highly non-proportional damping and the non-smooth nature of the nonlinearities.
2.
Integrating Experimental and Computational Fluid Dynamics approaches using Proper Orthogonal Decomposition Techniques - Andrianne, Thomas; Yasue, Kanako; Guissart, Amandine; Terrapon, Vincent; Dimitriadis, Grigorios; Kuchi-Ishi, Shigeru; Watanabe, Shigeya
The concept of Proper Orthogonal Decomposition (POD) is used to integrate Experimental Fluid Dynamics (EFD) and Computational Fluid Dynamics (CFD) approaches. The key idea is to take advantage of the optimality of the POD technique and its capability to extract the most energetic patterns of complex aerodynamic flow fields.
First, the concept of Modal Assurance Criterion (MAC) is used to obtain a simple quantitative criterion to compare EFD measurements to CFD results. The comparison is based on the POD modes, extracted from each set of data. The analysis of the energy content of the modes allows to draw important conclusions about...
13.
FAO Training in Crop Yield Forecasting. Improvement of the Crop Yield Forecasting System (CYFS) in Armenia: a new approach for satellite data integration. ARMENIA - Yerevan - January 2013. - Denis, Antoine
This manual describes a methodology to prepare the remote sensing database needed for the crop yield forecasting methodology developped by the University of Liege, in the case of Armenia.This manual has been written for the training in Crop Yield Forecasting for Armenia that occurred between 21st and 25th January 2013 in Erevan – Armenia in the framework of the “EC/FAO Programme on information systems to improve food security decision-making in the European Neighbourhood Policy (ENP) East area”. This manual is intended to cover the Remote Sensing part only of the general CYFS. Despite written for the Armenian training this manual...
14.
Validation of the Structural-Thermal-Model of the Small Earth Observation Satellite Flying Laptop - Steinmetz, Fabian; Lengowski, Michael; Winter, Daniel; Salvador, Lucas; Röser, Hans-Peter; Rochus, Pierre
Thorough thermal design and testing is compulsory for every satellite mission. A well-known thermal behavior of the entire satellite system is therefore indispensable and needs to be verified during the spacecraft development. A Structural-Thermal-Model (STM) was constructed for the Flying Laptop, a satellite currently being developed at the Institute of Space Systems (IRS) of the University of Stuttgart, which enables the validation of mechanical and thermal simulations for the satellite’s Flight-Model. The STM was vibration and thermal-vacuum tested at the Centre Spatial Liège (CSL). This paper will de-scribe the design and construction of the STM as well as the facilities...
15.
Validation of the Structural-Thermal Model of the Small Earth Observation Satellite Flying Laptop - Steinmetz, Fabian; Lengowski, Michael; Winter, Daniel; Salvador, Lucas; Röser, Hans-Peter; Rochus, Pierre
Thorough thermal design and testing is compulsory for every satellite mission. A well-known thermal behavior of the entire satellite system is therefore indispensable and needs to be verified during the spacecraft development. A Structural-Thermal-Model (STM) was constructed for the Flying Laptop, a satellite currently being developed at the Institute of Space Systems (IRS) of the University of Stuttgart, which enables the validation of mechanical and thermal simulations for the satellite’s Flight-Model. The STM was vibration and thermal-vacuum tested at the Centre Spatial Liège (CSL). This paper will de-scribe the design and construction of the STM as well as the facilities...
16.
Nonparametric subspace identification of nonlinear structures - Application to a spacecraft - Noël, Jean-Philippe; Kerschen, Gaëtan
The objective of the present paper is to address the identification of a strongly nonlinear
satellite structure by exploiting a new nonlinear subspace identification method formulated
in the frequency domain, referred to as the FNSI method. The modal parameters of
the underlying linear structure and the coefficients of the nonlinear internal forces will
be estimated by this approach. Moreover, because a priori knowledge about nonlinear
behaviour may be limited, the paper also proposes a nonparametric spline-based modelling
strategy, encapsulated in the FNSI method. The application of interest is the SmallSat
spacecraft developed by EADS-Astrium, which possesses an impact-type nonlinear device
consisting of eight mechanical stops limiting the motion...
17.
Dynamic Stall and Stall Flutter Simulations for a 2D Airfoil Using Viscous-Inviscid Coupling - Rothkegel Ide, José Ignacio; Dimitriadis, Grigorios
An interactive boundary layer model has been developed and coupled with a pitch plunge airfoil in 2d in order to solve the unsteady flow around the airfoil when undergoing light dynamic stall. The inviscid problem is solved by means of a panel method, by the discretization of the airfoil into vortex panels. The boundary layer is solved in a mixed manner, starting the solution in a direct way by imposing the external velocity and continuing it in an inverse way by imposing the displacement thickness. The solution of the boundary layer equations is carried out using a finite volume scheme....
18.
Damage detection and local resonances model in CFRP composite material by vibrothermography - Demy, Philippe; Golinval, Jean-Claude; Simon, Daniel
Vibrothermography (VT) is an active non destructive technique able to detect singularities like
delamination, even if the defect internal faces are in contact. Under sonic or ultrasonic mechanical
vibrations, a delamination may behave like a heat source principally due to friction between the rubbing faces and/or stress concentration in the area. The present article focuses on the understanding of the underlying phenomenon so-called "local resonances" and its correlation with the presence of temperature peaks observed at certain frequencies. For this purpose, a simplified finite element modal analysis of the delamination model is compared with the heating rate vs. frequency data's acquired by...
19.
Development of a high-order interior penalty discontinuous Galerkin method for compressible turbulent flows. Application to Reynolds-averaged Navier-Stokes and large eddy simulations - Drosson, Marcus
Over the last decade several studies and workgroups came to the conclusion that high-order discretisation schemes are the most suited to overcome the limitations of today’s flow solvers. The latter are at most second-order accurate and therefore often deliver poor results on currently used meshes. Within this context, discontinuous Galerkin (DG) methods have recently been identified as having the biggest potential for future flow solvers. Further research is however needed to improve the computational efficiency and the robustness of these schemes. Both issues are faced in the subsequent chapters of the thesis.
The first part of the thesis is devoted to...
20.
FAO Training in Crop Yield Forecasting. Crop Yield Forecasting Methodology Enhancement – Remote sensing. Erevan 21 - 25 January 2013. - Denis, Antoine
Power point presentation of the FAO training "Crop Yield Forecasting Methodology Enhancement – Remote sensing", held in Erevan, Armenia, 21 - 25 January 2013 at ARMSTATEHYDROMET. The main objective of this training was the improvement of the Crop Yield Forecasting System (CYFS) in Armenia by introducing a new approach for satellite data integration (use of TIMESAT software and METOP AVHRR NDVI images). This training was held in the framework of the "EC/FAO Programme on Information Systems to Improve Food Security Decision-Making in the European Neighbourhood Policy (ENP) East Area GCP/GLO/275/EC".
1.
