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During the past decades, the applications of braided composites have increased rapidly in a wide variety of sectors including aerospace, automotive, and marine industries. Their intensive use in engineering applications has inevitably created the need to build models in order to determine their mechanical properties. However, the beneficial qualities of braided composites come at a cost in terms of analysis: their mechanical behavior is significantly more difficult to model because of the intrinsic complexity of their architecture. The present work is carried out in collaboration with GDTech engineering and the University of Liège within the framework of the ViBra (i.e. Virtual Braiding) project, whose main goal is to set up reliable numerical simulation tools for the study of braided composites. Specifically, this thesis focuses on the evaluation of the effective elastic mechanical properties of two-dimensional triaxial braided composite materials through finite element analysis. The proposed approach is a homogenization-based multi-scale modeling procedure with a focus made on the meso-scale level. It requires the development of a robust and fully-parametrized model capable of generating the Representative Unit Cell (RUC) of any braided composite material. The model can generate lots of different braided architectures: in addition to the basic geometrical parameters, the model can adapt the tows cross-sectional shape, the undulation path of the tows, or the braiding pattern (i.e. diamond or regular). Material properties were assigned to each constituent of the RUC, taking into account the variation of local orthotropic direction of the fibers inside the tows. Combined with Periodic Boundary Conditions (PBC), homogenization simulations were performed and effective elastic properties were extracted. The methodology developed in the thesis is then validated by making a comparison between an article of the literature and results coming from the present model where a good agreement is achieved. Subsequently, a parametric study is performed to study the influence of the braiding angle on the effective elastic properties. The study is carried out on both diamond and regular braids, with a braiding angle varying from 15° to minimum 70°.

multi-scale modeling --- meso-scale model --- unit cell --- homogenization --- effective material properties --- triaxial braided composites --- Ingénierie, informatique & technologie > Ingénierie aérospatiale

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Currently, the use of computational fluid dynamics (CFD) solutions is considered as the state-of-the-art in the modeling of unsteady nonlinear flow physics and offers an early and improved understanding of air vehicle aerodynamics and stability and control characteristics. This Special Issue covers recent computational efforts on simulation of aerospace vehicles including fighter aircraft, rotorcraft, propeller driven vehicles, unmanned vehicle, projectiles, and air drop configurations. The complex flow physics of these configurations pose significant challenges in CFD modeling. Some of these challenges include prediction of vortical flows and shock waves, rapid maneuvering aircraft with fast moving control surfaces, and interactions between propellers and wing, fluid and structure, boundary layer and shock waves. Additional topic of interest in this Special Issue is the use of CFD tools in aircraft design and flight mechanics. The problem with these applications is the computational cost involved, particularly if this is viewed as a brute-force calculation of vehicle’s aerodynamics through its flight envelope. To make progress in routinely using of CFD in aircraft design, methods based on sampling, model updating and system identification should be considered.

numerical methods --- modeling --- aerodynamics --- Taylor–Green vortex --- slender-body --- neural networks --- shock-channel --- wind gust responses --- installed propeller --- bifurcation --- RANS --- wake --- multi-directional --- bluff body --- MDO --- variable fidelity --- computational fluid dynamics (CFD) --- high angles of attack --- aeroelasticity --- computational fluid dynamics --- wind tunnel --- Godunov method --- flow control --- unsteady aerodynamic characteristics --- overset grid approach --- convolution integral --- MUSCL --- DDES --- dynamic Smagorinsky subgrid-scale model --- CPACS --- flutter --- reduced-order model --- meshing --- vortex generators --- hybrid reduced-order model --- microfluidics --- Riemann solver --- characteristics-based scheme --- CFD --- wing–propeller aerodynamic interaction --- kinetic energy dissipation --- Euler --- formation --- square cylinder --- multi-fidelity --- turbulence model --- subsonic --- large eddy simulation --- after-body --- flow distortion --- VLM --- numerical dissipation --- hypersonic --- modified equation analysis --- fluid mechanics --- reduced order aerodynamic model --- p-factor --- URANS --- flexible wings --- chemistry --- detection --- microelectromechanical systems (MEMS) --- angle of attack --- sharp-edge gust --- truncation error --- aerodynamic performance --- quasi-analytical --- gasdynamics --- discontinuous Galerkin finite element method (DG–FEM) --- geometry --- S-duct diffuser

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Modern power and energy systems are characterized by the wide integration of distributed generation, storage and electric vehicles, adoption of ICT solutions, and interconnection of different energy carriers and consumer engagement, posing new challenges and creating new opportunities. Advanced testing and validation methods are needed to efficiently validate power equipment and controls in the contemporary complex environment and support the transition to a cleaner and sustainable energy system. Real-time hardware-in-the-loop (HIL) simulation has proven to be an effective method for validating and de-risking power system equipment in highly realistic, flexible, and repeatable conditions. Controller hardware-in-the-loop (CHIL) and power hardware-in-the-loop (PHIL) are the two main HIL simulation methods used in industry and academia that contribute to system-level testing enhancement by exploiting the flexibility of digital simulations in testing actual controllers and power equipment. This book addresses recent advances in real-time HIL simulation in several domains (also in new and promising areas), including technique improvements to promote its wider use. It is composed of 14 papers dealing with advances in HIL testing of power electronic converters, power system protection, modeling for real-time digital simulation, co-simulation, geographically distributed HIL, and multiphysics HIL, among other topics.

Technology: general issues --- design methodology --- FPGA --- hardware in the loop --- LabVIEW --- real-time simulation --- power converters --- HIL --- CHIL --- integrated laboratories --- real-time communication platform --- power system testing --- co-simulation --- geographically distributed simulations --- power system protection and control --- holistic testing --- lab testing --- field testing --- PHIL --- PSIL --- pre-certification --- smart grids --- standards --- replica controller --- TCSC --- DPT --- testing --- control and protection --- large-scale power system --- voltage regulation --- distribution system --- power hardware-in-the-loop --- distributed energy resources --- extremum seeking control --- particle swarm optimization --- state estimation --- reactive power support --- volt–VAR --- model-based design --- multi physics simulation --- marine propulsion --- ship dynamic --- DC microgrid --- shipboard power systems --- under-frequency load shedding --- intelligent electronic device --- proof of concept --- hardware-in-the-loop testing --- real-time digital simulator --- frequency stability margin --- rate-of-change-of-frequency --- geographically distributed real-time simulation --- remote power hardware-in-the-Loop --- grid-forming converter --- hardware-in-the-loop --- simulation fidelity --- energy-based metric --- energy residual --- quasi-stationary --- Hardware-in-the-Loop (HIL) --- Control HIL (CHIL) --- Power HIL (PHIL) --- testing of smart grid technologies --- power electronics --- shifted frequency analysis --- dynamic phasors --- real-time hybrid-simulator (RTHS) --- hybrid simulation --- hardware-in-the-loop simulation (HILS) --- dynamic performance test (DPT) --- real-time simulator (RTS) --- testing of replicas --- multi-rate simulation --- EMT --- control --- inverters --- inverter-dominated grids --- power system transients --- predictive control --- hydro-electric plant --- variable speed operation --- ‘Hill Charts’ --- reduced-scale model --- testing and validation

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Satisfactory acoustics is crucial for the ability of spaces such as auditoriums and lecture rooms to perform their primary function. The acoustics of dwellings and offices greatly affects the quality of our life, since we are all consciously or subconsciously aware of the sounds to which we are daily subjected. Architectural acoustics, which encompasses room and building acoustics, is the scientific field that deals with these topics and can be defined as the study of generation, propagation, and effects of sound in enclosures. Modeling techniques, as well as related acoustic theories for accurately calculating the sound field, have been the center of many major new developments. In addition, the image conveyed by a purely physical description of sound would be incomplete without regarding human perception; hence, the interrelation between objective stimuli and subjective sensations is a field of important investigations. A holistic approach in terms of research and practice is the optimum way for solving the perplexing problems which arise in the design or refurbishment of spaces, since current trends in contemporary architecture, such as transparency, openness, and preference for bare sound-reflecting surfaces are continuing pushing the very limits of functional acoustics. All the advances in architectural acoustics gathered in this Special Issue, we hope that inspire researchers and acousticians to explore new directions in this age of scientific convergence.

Research & information: general --- Mathematics & science --- acoustic measurements --- impulse response measurements --- omnidirectional source --- dodecahedron --- acoustic parameters --- sound source --- reverberation time --- ISO 3382 --- auralization --- sound absorption --- perforated panels --- micro-perforated panels --- resonant absorbers --- frequency domain --- PUFEM --- room acoustics --- wave-based method --- discretization error --- explicit method --- finite element method --- high order scheme --- room acoustic simulations --- time domain --- shoebox concert hall --- diffusive surfaces --- diffusers location --- acoustical parameters --- variable acoustics --- subjective investigation --- acoustics --- opera house --- intangible cultural heritage --- open-air ancient theatres --- ISO 3382-1 --- firecrackers --- building acoustics --- sound absorption coefficient --- prediction models --- supervised learning method --- worship space acoustics --- acoustics simulation --- acoustic heritage --- archaeo-acoustics --- acoustic subspaces --- FDTD simulation --- speech intelligibility --- open-plan offices --- spatial decay --- ISO 3382-3 --- room absorption --- office noise --- speech --- calculation models --- absorption --- scattering --- airflow resistivity --- long space --- coherent image source method --- sound-absorbing boundary --- sound field modeling --- scale-model experiment --- reflection power --- room response --- directional decay rates --- room modes --- eigenbeam processing --- spatial correlation --- concert hall acoustics --- lateral reflections --- shoebox typology --- spatial impression --- perception thresholds --- skeletal reflections --- reflection sequence --- seat dip effect --- seat height --- seat spacing --- mechanism --- n/a

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This book aims to provide research and engineering applications related to water and hydraulic problems. It is comprised of scientific papers in all topics of hydraulics, in particular, on sustainable water management, environmental hydraulics, ecohydraulics, water–energy nexus, and systems protection and efficiency. Safety and innovation issues, interdisciplinary problems, and linkage of theory to experimental and field applications can also be found within. Solutions of water problems in the form of prediction models, flow simulations, engineering systems, monitoring, management strategies covering scientific investigations and/or experimental or field studies of flow behaviour, hydrodynamics, and climate changes effects and adaptation, new design solutions, innovative approaches in the field of environment, hydraulics, techniques, methods, and analyses to address the new challenges in environmental hydraulics are alo presented and explored. This topic is studied both from a technical and environmental point of view, with the objective of protecting and enhancing the quality of the environment. In a cross-disciplinary field of study, this book comprises open channel/river flows and pressurised systems, combining, among others, new technological, social, and environmental hydraulic challenges, working in water-related fields with available information, new concepts and tools, new design solutions, eco-friendly technologies, and the advanced materials necessary to address the increasing challenges of ensuring a sustainable water environment by promoting the adaptation, flexibility, integration, and sustainability of recognised environmental solutions.

Technology: general issues --- water well --- hydraulic efficiency --- degradation --- engineering structure --- well ageing --- lifespan --- well operation --- water well management --- sustainable efficiency --- frozen soil --- soil freezing curve --- hydraulic conductivity --- fractal model --- Darcy’s law --- dissolved phosphorus --- hydrodynamic condition --- Lattice Boltzmann method --- release characteristics --- stormwater reuse --- SCS curve number --- CFD --- fecal indicator bacteria --- E. coli --- fish protection --- head loss --- intake --- hydraulics of renewable energy systems --- hydraulic structure design and management --- scale model test --- canal pool --- delay time --- volume compensation --- feedforward control --- downstream constant water level --- toothed internal energy dissipaters (TIED) --- area contraction ratio --- over-current capability --- energy dissipation rate --- time-averaged pressure --- pulsating pressure --- time-averaged velocity --- pulsating velocity --- water level --- Three Gorges Dam --- hydrodynamic model --- river–lake system --- Poyang Lake --- jet falling --- energy dissipation --- surface disturbances --- pressure fluctuations --- water jet --- physical modeling --- water flow diversity --- permeable spur dike --- fish aggregation effect --- channel regulation --- suspended vegetation --- FTW --- ADV --- velocity profile --- submerge ratio --- SVF --- hydro-energy --- CAES --- transient flow --- energy concept --- energy storage --- similarity law --- erosion --- cohesive sediments --- rotating circular flume --- mathematical modelling --- fitting coefficients --- sediment deposition --- flocculation --- bed shear stress --- consolidation --- hydrostatic pressure machine --- micro hydropower --- open source --- sliding mesh --- volume of fluid --- caffa3d --- pumped hydro storage (PHS) --- hybrid hydro-wind-solar solutions --- technical feasibility --- new power generation --- new hydraulic concepts --- sustainable developments --- CFD models --- water systems efficiency --- hydropower systems --- eco-design --- environmentally-friendly solutions --- hydrologic and ecologic challenges --- hydraulic structures --- free surface flows --- pressurised flows --- soil structure --- groundwater --- erosion and energy dissipaters --- hydrodynamics