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Rotating detonation Engines (RDE) are a novel technique in pressure gain combustion. In this type of combustion the theoretical efficiency gain achievable is not possible using traditional combustion techniques. The dynamics of the rotating detonation engines is complex, and high dimensional. Reduced order modelling are tools that can be used to reduce the high dimensional nature of these systems. Dynamic Mode Decomposition is one such technique. Dynamics in the rotating detonation engine manifests itself in two major forms. The first is a spinning wave form in which a single detonation wave that travels around the annulus of the engine at a very fast rate. The second is a clapping wave form which is obtained when two counterrotating waves interact with each other around the annulus. A robust dynamic mode decomposition algorithm is developed and it is benchmarked using synthetic data generated using mathematical formulations. Synthetic data is generated to mimic the dynamics present in the rotating detonation engine. Once the algorithm has been sufficiently tested and validated it is applied to the experimental data. High speed images of the aft end of the rotating detonation engine is used, the dynamic mode decomposition algorithm is then applied to this data and it is demonstrated that the dynamics of the system can be predicted using few dynamic modes and frequencies. However it was found that the error is still large and has to be reduced in order to create a reliable and accurate reduced order model of the engine. The images are then modified to isolate the region where the detonation wave operates. DMD on reduced set of images produces degenerate modes. The number of snapshot taken for analysis was shown to affect the accuracy and presence of so called degenerate modes. It was shown that the best accuracy value was achieved when the number of snapshots is equal to the number of the modes taken. It was further shown that for this test case the best accuracy was obtained using just 50 snapshots and 50 singular modes. Long term validity of the parameters obtained i.e. the number of snapshots and number of modes retained was demonstrated. It was seen that the frequencies and reconstruction error converge and oscillate around a mean. The maximum deviation of these parameters was within acceptable limits. The mode shapes also converge thus indicating that the parameters are valid for the whole test case. This also proved that there are no transients in the test case.

Dynamic Mode Decomposition, Rotating Detonation Engines, Reduced Order Modelling --- Ingénierie, informatique & technologie > Ingénierie aérospatiale

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This book develops a fundamental understanding of geophysical fluid dynamics based on a mathematical description of the flows of inhomogeneous fluids. It covers these topics: 1. development of the equations of motion for an inhomogeneous fluid 2. review of thermodynamics 3. thermodynamic and kinetic energy equations 4. equations of state for the atmosphere and the ocean, salt, and moisture effects 5. concepts of potential temperature and potential density 6. Boussinesq and quasi-geostrophic approximations 7. conservation equations for vorticity, mechanical and thermal energy instability theories, internal waves, mixing, convection, double-diffusion, stratified turbulence, fronts, intrusions, gravity currents Graduate students will be able to learn and apply the basic theory of geophysical fluid dynamics of inhomogeneous fluids on a rotating earth, including: 1. derivation of the governing equations for a stratified fluid starting from basic principles of physics 2. review of thermodynamics, equations of state, isothermal, adiabatic, isentropic changes 3. scaling of the equations, Boussinesq approximation, applied to the ocean and the atmosphere 4. examples of stratified flows at geophysical scales, steady and unsteady motions, inertia-gravity internal waves, quasi-geostrophic theory 5. vorticity and energy conservation in stratified fluids 6.boundary layer convection in stratified containers and basins.

Oceanography. --- Meteorology. --- Coasts. --- Hydrology. --- Geophysics. --- Coastal Sciences. --- Hydrology/Water Resources. --- Geophysics and Environmental Physics. --- Geological physics --- Terrestrial physics --- Earth sciences --- Physics --- Aquatic sciences --- Hydrography --- Water --- Coastal landforms --- Coastal zones --- Coastlines --- Landforms --- Seashore --- Aerology --- Atmospheric science --- Oceanology --- Thalassography --- Marine sciences --- Geophysics --- Fluid models. --- Fluid models in geophysics --- Rotating dishpan

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Severe plastic deformation (SPD) is a very attractive research field for metallic materials because it provides new possibilities for manufacturing nanostructured materials in large quantities and allows microstructural design on different hierarchical levels. The papers included in this issue address the following topics: novel SPD processes as well as recent advancements in established processing methods, microstructure evolution and grain refinement in single- and multi-phase alloys as well as composites, strategies to enhance the microstructure stability at elevated temperatures, mechanically driven phase transformations, surface nanostructuring, gradient and multilayered materials, and mechanical and physical properties of SPD-processed materials.

Mg-3.7Al-1.8Ca-0.4Mn alloy --- Al2Ca phase --- equal channel angular pressing --- refinement --- mechanical properties --- aluminium copper-clad rod --- hardness --- effective electrical conductivity --- severe plastic deformation --- Mg-9Li duplex alloy --- ECAP --- rolling --- high strength --- microstructure --- high pressure torsion extrusion --- gradient structure --- hardness distribution --- tensile properties --- copper --- high pressure torsion --- microstructural characterization --- magnetic properties --- hysteresis --- magneto-resistance --- β titanium alloys --- α phase precipitation --- phase composition --- high energy synchrotron X-ray diffraction --- metastable β-Ti alloys --- powder metallurgy --- cryogenic milling --- spark plasma sintering --- surface mechanical attrition treatment (SMAT) --- ultrasonic shot peening (USP) --- functionally graded materials (FGM) --- titanium niobium alloys --- titanium molybdenum alloys --- human mesenchymal stem cells culture --- cell adhesion --- cell proliferation --- magnesium --- equal-channel angular pressing --- deformation tests --- texture --- schmid factor --- cryogenic temperature --- 304L austenitic stainless steel --- rotating–bending fatigue --- tension–compression fatigue --- TiNi alloy --- thermal cycling --- ultrafine-grained structure --- microstructural and mechanical stability --- Ti–Fe --- high-pressure torsion --- high-temperature XRD --- differential scanning calorimetry --- phase diagram --- CalPhaD --- Mg alloy --- severe plastic deformation (SPD) --- intermetallic precipitates --- vacancy agglomerates --- corrosion --- n/a --- rotating-bending fatigue --- tension-compression fatigue --- Ti-Fe

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Fluid interfaces are promising candidates for confining different types of materials, e.g., polymers, surfactants, colloids, and even small molecules, to be used in designing new functional materials with reduced dimensionality. The development of such materials requires a deepening of the physicochemical bases underlying the formation of layers at fluid interfaces as well as on the characterization of their structures and properties. This is of particular importance because the constraints associated with the assembly of materials at the interface lead to the emergence of equilibrium and features of dynamics in the interfacial systems, which are far removed from those conventionally found in traditional materials. This Special Issue is devoted to studies on the fundamental and applied aspects of fluid interfaces, and attempts to provide a comprehensive perspective on the current status of the research field.

Technology: general issues --- polyelectrolyte --- surfactants --- kinetically trapped aggregates --- interfaces --- surface tension --- interfacial dilational rheology --- adsorption --- nonlinear stretching sheet --- viscoelastic fluid --- MHD --- viscous dissipation --- underwater vehicle --- sea-water pump --- vibration isolation --- flexible pipes --- cationic surfactants --- Gemini 12-2-12 surfactant --- dynamic surface tension --- maximum bubble pressure --- surface potential --- nanofluid --- stretching surface --- rotating fluid --- Homotopy Analysis Method (HAM) --- porous media --- magnetohydrodynamics --- hybrid nanofluid --- stretching cylinder --- flow characteristics --- nanoparticles --- convective heat transfer --- interfacial tensions --- dilational rheology --- biocompatible emulsions --- partition coefficient --- Tween 80 --- saponin --- citronellol glucoside --- MCT oil --- Miglyol 812N --- lipids --- pollutants --- Langmuir monolayers --- particles --- rheology --- neutron reflectometry --- ellipsometry --- DPPC --- lipid monolayers --- air/water interface --- entropy --- second grade nanofluid --- Cattaneo-Christov heat flux model --- nonlinear thermal radiation --- Joule heating --- fluid displacement --- inverse Saffman–Taylor instability --- partially miscible --- Korteweg force --- gyrotactic microorganisms --- micropolar magnetohydrodynamics (MHD) --- Maxwell nanofluid --- single wall carbon nanotubes (SWCNTs) and multi wall carbon nanotubes (MWCNTs) --- thermal radiation --- chemical reaction --- mixed convection --- permeability --- confinement --- dynamics --- materials --- applications

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This book is a comprehensive set of articles reflecting the latest advances and developments in mathematical modeling and the design of electrical machines for different applications. The main models discussed are based on the: i) Maxwell–Fourier method (i.e., the formal resolution of Maxwell’s equations by using the separation of variables method and the Fourier’s series in 2-D or 3-D with a quasi-Cartesian or polar coordinate system); ii) electrical, thermal and magnetic equivalent circuit; iii) hybrid model. In these different papers, the numerical method and the experimental tests have been used as comparisons or validations.

History of engineering & technology --- surface-mounted PM machines --- torque pulsation --- magnet shape optimization --- analytical expression --- 2D --- electromagnetic performances --- finite iron relative permeability --- numerical --- sinusoidal current excitation --- subdomain technique --- switched reluctance machine --- scattering matrix --- Fourier analysis --- permanent magnet machines --- analytical modeling --- analytical model --- high-speed --- sleeve --- non-homogeneous permeability --- permanent-magnet --- partial differential equations --- separation of variable technique --- electrical machines --- surface inset permanent magnet --- electric machines --- permanent magnet motor --- rotating machines --- hybrid excitation --- magnetic equivalent circuits --- 3D finite element method --- eddy-current losses --- experiment --- hybrid model --- magnetic equivalent circuit --- Maxwell–Fourier method --- analytical method --- eddy-current --- finite-element analysis --- loss reduction --- permanent-magnet losses --- thermal analysis --- linear induction motors --- complex harmonic modeling --- hybrid analytical modeling --- 2D steady-state models --- multiphase induction machine --- reduced order --- rotor cage --- torque pulsations --- multi-phase --- segmentation --- synchronous machines --- thermal equivalence circuit --- Voronoï tessellation --- winding heads --- nodal method --- thermal resistances --- n/a --- Maxwell-Fourier method --- Voronoï tessellation