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Aerodynamic Performance and Wake Validation of Micro Wind Turbines Using CFD and SPIV
No full textInternational audienceThis study investigates the aerodynamic performance and wake characteristics of a micro horizontal axis wind turbine by combining computational fluid dynamics simulation with Stereo Particle Image Velocimetry (SPIV) experiments. The micro wind turbine adopts an high solidity cascade design, which is suitable for low Reynolds number conditions. The study evaluates the performance and wake characteristics of this type of wind turbine. The CFD analysis, based on a Reynolds-averaged Navier-Stokes (RANS) approach using the k-ε turbulence model, includes the evaluation of power and torque coefficients, as well as the velocity field in the wake region. The wake structures predicted by the CFD show strong agreement with the SPIV measurements, particularly in the axial and tangential velocity distributions. In addition, the power coefficient derived from CFD simulations exhibits good consistency with the experimentally measured values obtained from torque-based power measurements, with a relative error of approximately 3.75%. The study provides a theoretical basis for the design optimization of micro wind turbines, especially in the blade cascade design, which helps to improve the performance and efficiency of distributed wind energy systems
Modal analysis of the triadic interactions in the dynamics of a transitional shock wave boundary layer interaction
No full textInternational audienceThis work is a numerical study of a transitional shock wave boundary layer interaction (SWBLI). The main goal is to improve our understanding of the well-known low-frequency SWBLI unsteadiness and especially the suspected role of triadic interactions in the underlying physical mechanism. To this end, a direct numerical simulation is performed using a high-order finite-volume scheme equipped with a suitable shock capturing procedure. The resulting database is then extensively post-processed in order to extract the main dynamical features of the interaction zone dynamics (involved characteristic frequencies, characteristics of the vortical structures, etc.). The dynamical organisation and space–time evolution of the flow at dominant frequencies are then further characterised by mean of an spectral proper orthogonal decomposition analysis. In order to study the role of triadic interactions occurring in the interaction region, a bispectral mode decomposition analysis is applied to the database. It allows us to extract the significant triadic interactions, their location and the resulting physical spatial modes. Strong triadic interactions are detected in the downstream part of the separation bubble whose role on the low-frequency unsteadiness is characterised. All the results of the various analyses are then discussed and integrated to formulate a possible mechanism fuelling low-frequency SWBLI unsteadiness
Cities and Urban areas with Mobility based on Innovation and carbon Neutrality: CUMIN programme extension
No full textInternational audienceTo limit the global warming, the greenhouse gases (GHG) have to be reduced. In Europe the transport is one of the main contributor to GHG. Since 2010, University of Lille does regularly a carbon footprint report. The commuting represents more than 50% of its GHG. In 2016, the CUMIN (Campus of University with Mobility based on Innovation and carbon Neutrality) interdisciplinary programme of University of Lille has been developed to propose electromobility solutions to contribute to a significant reduction of the commuting GHG. This research program is now extended to "Cities and urban areas". CUMIN develops a crossdisciplinary approach combining technological, economic and social aspects. It brings together 3 research groups on sciences & technologies, 3 research groups on human & social sciences and the MEL (Métrople Européenne de Lille). The CUMIN programme is presented and first results are discussed
Proposition d’une méthodologie de coopération humain-robot : application à une cellule de désassemblage robotisée
No full textInternational audienceDans le domaine du désassemblage d’appareils électrotechniques, la coopération humain-robot est devenue essentielle. Si les systèmes autonomes progressent, la diversité des produits rend le travail manuel nécessaire. Dès lors, il est crucial de mettre en place une coopération efficiente entre humains et robots. Celle-ci repose sur l’adaptabilité humaine, l’efficacité du robot et une communication entre eux pour anticiper les tâches de désassemblage, tout en priorisant la prise de décision par l’humain et les interactions entre les agents
Real-time forging process control: integrating billet-related surrogate and machine behavior models
No full textInternational audienceThis study introduces a predictive surrogate model for real-time control in cold upsetting processes, incorporating both material and machine behaviors. Traditional approaches often simplify machine behavior as rigid or with constant stiffness; however, the proposed method dynamically couples material and machine responses, accounting for efficiency changes across different upsetting operations. This is achieved through the integration of a data-driven billet-related surrogate model with a machine-related analytical blow efficiency prediction, accurately capturing elastic energy losses. For the construction of the surrogate model in this use case, a multilayer perceptron artificial neural network (MLP ANN) was employed, demonstrating high predictive accuracy with a dataset comprising 2000 entries generated using Latin Hypercube Sampling (LHS) and numerical simulations. The model provides precise predictions for key outputs like forging load and plastic energy. Experimental validation shows prediction errors below 5% for energy setpoints, reduced to under 1% with blow efficiency correction. The general methodology of surrogate model creation can be adapted for various metal-forming processes, providing a versatile framework for real-time simulation and control
Neural Network-Based Metamodel of synthetic seismograms: Application for uncertainty quantification
No full textInternational audienc
SHM for Complex Composite Aerospace Structures: A Case Study on Engine Fan Blades
No full textInternational audienceComposite engine fan blades are critical aircraft engine components, and their failure can compromise the safe and reliable operation of the entire aircraft. To enhance aircraft availability and safety within a condition-based maintenance framework, effective methods are needed to identify damage and monitor the blades’ condition throughout manufacturing and operation. This paper presents a unique experimental framework for real-time monitoring of composite engine blades utilizing state-of-the-art structural health monitoring (SHM) technologies, discussing the associated benefits and challenges. A case study is conducted on a representative Foreign Object Damage (FOD) panel, a substructure of a LEAP (Leading Edge Aviation Propulsion) engine fan blade, which is a curved, 3D-woven Carbon Fiber Reinforced Polymer (CFRP) panel with a secondary bonded steel leading edge. The loading scheme involves incrementally increasing, cyclic 4-point bending (loading–unloading) to induce controlled damage growth, simulating in-operation conditions and allowing evaluation of flexural properties before and after degradation. External damage, simulating foreign object impact common during flight, is introduced using a drop tower apparatus either before or during testing. The panel’s condition is monitored in-situ and in real time by two types of SHM sensors: screen-printed piezoelectric sensors for guided ultrasonic wave propagation studies and surface-bonded Fiber Bragg Grating (FBG) strain sensors. Experiments are conducted until panel collapse, and degradation is quantified by the reduction in initial stiffness, derived from the experimental load-displacement curves. This paper aims to demonstrate this unique experimental setup and the resulting SHM data, highlighting both the potential and challenges of this SHM framework for monitoring complex composite structures, while an attempt is made at correlating SHM data with structural degradation
Determination of a suitable molar absorption coefficient (ε) for lignin analysis of fibrous plants using the CASA method
No full textInternational audienceIn this study, the benchmarking and applicability of the CASA method for the analysis of fibrous plants, such as flax, hemp, and jute, is evaluated. Lignin is a phenolic biopolymer present in plant cell walls and is composed of three primary monomeric units, designated G, S, and H. Various factors, such as the genetic variability, influence the relative proportions of these units in plant samples. Recently, the cysteine-assisted sulfuric acid (CASA) method has been introduced as a rapid method for the quantification of lignin in wood samples. The aim of this study is to establish a suitable molar absorption coefficient (ε, L·g−1·cm−1) to adapt the CASA method for use with annual plant fibers. This investigation was motivated by the technical advantages of the CASA method, including higher throughput, lower reaction temperatures, and ecological benefits due to the absence of carcinogenic, mutagenic, or reprotoxic (CMR) substances and the need for minimal sample quantities. In this method, lignin solubilization is facilitated by cysteine, which is an amino acid that enhances the reaction kinetics, using a one-hour incubation period. However, as with any spectrophotometric technique, the CASA method depends on a molar absorption coefficient (ε) that varies according to the ratio of the aromatic units within the polymer. To evaluate the suitability of CASA for quantifying lignin in economically significant plant fibers, we investigate the impact of the unit ratios on the accuracy of ε. The results are compared with those of two widely recognized lignin analytical methods: the Klason method, which is a gravimetric reference method, and the acetyl bromide soluble lignin method, which is the most commonly used spectrophotometric approach. The final ε obtained in this study reveals a relative difference in lignin content ranging from −8 % to +9 % based on a comparison between the CASA and Klason methods across different industrial hemp varieties. Using known G:S ratios in annual fibrous plants, ε can be estimated from our results
EDUCAUSE 2024 French Delegation Report - EN: EDUCAUSE Teaching & Learning Symposium 2024Visits to Houston Community College, Texas A&M University, San Antonio College, University of Texas San Antonio
No full textThe Annual Conference 2023 held in Chicago in October marked the 10th anniversary of the EDUCAUSEFrench Delegation. This milestone is obviously an opportunity for us to look back on the road travelled in adecade.From the beginning, this initiative has sought to provide the French higher education community with aninternational perspective on digital issues, by bringing together complementary profiles capable of assessing themajor trends and prospects. This has taken the form of ongoing participation in the EDUCAUSE AnnualConferences since 2013, which has been significantly enriched over the years. From an initial philosophy ofsimple participation that prevailed in the early years, the members of this Delegation have gradually becomeinvolved at various levels of EDUCAUSE, within the framework of the conferences and beyond (see theinfographic below).We have now selected twenty presentations on a range of topical subjects. Several of our members are alsoinvolved each year as proposal reviewers for the EDUCAUSE Annual Conference, and as members of therespective programme committees (in 2019 and 2023). Finally, some of us sit on expert panels for theEDUCAUSE Horizon Report and the annual Top-10 issues, are active in various thematic Community Groups(XR and Learning Spaces in particular), or are involved as writers of reference articles and translators of tools.We should also mention the nearly thirty site visits that have also been carried out since 2013 before or after theEDUCAUSE Annual Conferences, which, in addition to the remarkable welcome we have always received, haveprovided us with an invaluable insight into the field through high-quality discussions