Littérature scientifique sur le sujet « Idealised configuration »
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Articles de revues sur le sujet "Idealised configuration"
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Maher, Penelope, et Paul Earnshaw. « The Flexible Modelling Framework for the Met Office Unified Model (Flex-UM, using UM 12.0 release) ». Geoscientific Model Development 15, no 3 (9 février 2022) : 1177–94. http://dx.doi.org/10.5194/gmd-15-1177-2022.
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Abstract. The Met Office Unified Model (UM) is a world-leading atmospheric weather and climate model. In addition to comprehensive simulations of the atmosphere, the UM is capable of running idealised simulations, such as the dry physics Held–Suarez test case, radiative convective equilibrium and simulating planetary atmospheres other than Earth. However, there is a disconnect between the simplicity of the idealised UM model configurations and the full complexity of the UM. This gap inhibits the broad use of climate model hierarchy approaches within the UM. To fill this gap, we have developed the Flexible Modelling Framework for the UM – Flex-UM – which broadens the climate model hierarchy capabilities within the UM. Flex-UM was designed to replicate the atmospheric physics of the Geophysical Fluid Dynamics Laboratory (GFDL) idealised moist physics aqua-planet model. New parameterisations have been implemented in Flex-UM, including simplified schemes for convection, large-scale precipitation, radiation, boundary layer and sea surface temperature (SST) boundary conditions. These idealised parameterisations have been implemented in a modular way, so that each scheme is available for use in any model configuration. This has the advantage that we can incrementally add or remove complexity within the model hierarchy. We compare Flex-UM to ERA5 and aqua-planet simulations using the Isca climate modelling framework (based on the GFDL moist physics aqua-planet model) and comprehensive simulations of the UM (using the GA7.0 configuration). We also use two SST boundary conditions to compare the models (fixed SST and a slab ocean). We find the Flex-UM climatologies are similar to both Isca and GA7.0 (though Flex-UM is generally a little cooler, with higher relative humidity and a less pronounced storm track). Flex-UM has a single Intertropical Convergence Zone (ITCZ) in the slab-ocean simulation but a double-ITCZ in the fixed-SST simulation. Further work is needed to ensure that the atmospheric energy budget closes to within 1–2 W m−2, as the current configuration of Flex-UM gains 9–11 W m−2 (the range covers the two SST boundary conditions). Flex-UM greatly extends the modelling hierarchy capabilities of the UM and offers a simplified framework for developing, testing and evaluating parameterisations within the UM.
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Schröter, Jennifer, Daniel Rieger, Christian Stassen, Heike Vogel, Michael Weimer, Sven Werchner, Jochen Förstner et al. « ICON-ART 2.1 : a flexible tracer framework and its application for composition studies in numerical weather forecasting and climate simulations ». Geoscientific Model Development 11, no 10 (5 octobre 2018) : 4043–68. http://dx.doi.org/10.5194/gmd-11-4043-2018.
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Abstract. Atmospheric composition studies on weather and climate timescales require flexible, scalable models. The ICOsahedral Nonhydrostatic model with Aerosols and Reactive Trace gases (ICON-ART) provides such an environment. Here, we introduce the most up-to-date version of the flexible tracer framework for ICON-ART and explain its application in one numerical weather forecast and one climate related case study. We demonstrate the implementation of idealised tracers and chemistry tendencies of different complexity using the ART infrastructure. Using different ICON physics configurations for weather and climate with ART, we perform integrations on different timescales, illustrating the model's performance. First, we present a hindcast experiment for the 2002 ozone hole split with two different ozone chemistry schemes using the numerical weather prediction physics configuration. We compare the hindcast with observations and discuss the confinement of the vortex split using an idealised tracer diagnostic. Secondly, we study AMIP-type integrations using a simplified chemistry scheme in conjunction with the climate physics configuration. We use two different simulations: the interactive simulation, where modelled ozone is coupled back to the radiation scheme, and the non-interactive simulation that uses a default background climatology of ozone. Additionally, we introduce changes of water vapour by methane oxidation for the interactive simulation. We discuss the impact of stratospheric ozone and water vapour variations in the interactive and non-interactive integrations on the water vapour tape recorder, as a measure of tropical upwelling changes. Additionally we explain the seasonal evolution and latitudinal distribution of the age of air. The age of air is a measure of the strength of the meridional overturning circulation with young air in the tropical upwelling region and older air in polar winter downwelling regions. We conclude that our flexible tracer framework allows for tailor-made configurations of ICON-ART in weather and climate applications that are easy to configure and run well.
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Manchester, Emily Louise, Dylan Roi, Boram Gu, Xiao Yun Xu et Kyriakos Lobotesis. « Modelling Combined Intravenous Thrombolysis and Mechanical Thrombectomy in Acute Ischaemic Stroke : Understanding the Relationship between Stent Retriever Configuration and Clot Lysis Mechanisms ». Life 11, no 11 (20 novembre 2021) : 1271. http://dx.doi.org/10.3390/life11111271.
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Background: Combined intravenous thrombolysis and mechanical thrombectomy (IVT-MT) is a common treatment in acute ischaemic stroke, however the interaction between IVT and MT from a physiological standpoint is poorly understood. In this pilot study, we conduct numerical simulations of combined IVT-MT with various idealised stent retriever configurations to evaluate performance in terms of complete recanalisation times and lysis patterns. Methods: A 3D patient-specific geometry of a terminal internal carotid artery with anterior and middle cerebral arteries is reconstructed, and a thrombus is artificially implanted in the MCA branch. Various idealised stent retriever configurations are implemented by varying stent diameter and stent placement, and a configuration without a stent retriever provides a baseline for comparison. A previously validated multi-level model of thrombolysis is used, which incorporates blood flow, drug transport, and fibrinolytic reactions within a fibrin thrombus. Results: Fastest total recanalisation was achieved in the thrombus without a stent retriever, with lysis times increasing with stent retriever diameter. Two mechanisms of clot lysis were established: axial and radial permeation. Axial permeation from the clot front was the primary mechanism of lysis in all configurations, as it facilitated increased protein binding with fibrin fibres. Introducing a stent retriever channel allowed for radial permeation, which occurred at the fluid-thrombus interface, although lysis was much slower in the radial direction because of weaker secondary velocities. Conclusions: Numerical models can be used to better understand the complex physiological relationship between IVT and MT. Two different mechanisms of lysis were established, providing a basis towards improving the efficacy of combined treatments.
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Eberhard, Julius, Oliver E. Bevan, Georg Feulner, Stefan Petri, Jeroen van Hunen et James U. L. Baldini. « Sensitivity of Neoproterozoic snowball-Earth inceptions to continental configuration, orbital geometry, and volcanism ». Climate of the Past 19, no 11 (6 novembre 2023) : 2203–35. http://dx.doi.org/10.5194/cp-19-2203-2023.
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Abstract. The Cryogenian period (720–635 million years ago) in the Neoproterozoic era featured two phases of global or near-global ice cover termed “snowball Earth”. Climate models of all kinds indicate that the inception of these phases must have occurred in the course of a self-amplifying ice–albedo feedback that forced the climate from a partially ice-covered to a snowball state within a few years or decades. The maximum concentration of atmospheric carbon dioxide (CO2) allowing such a drastic shift depends on the choice of model, the boundary conditions prescribed in the model, and the amount of climatic variability. Many previous studies reported values or ranges for this CO2 threshold but typically tested only a very few different boundary conditions or excluded variability due to volcanism. Here we present a comprehensive sensitivity study determining the CO2 thresholds in different scenarios for the Cryogenian continental configuration, orbital geometry, and short-term volcanic cooling effects in a consistent model framework using the climate model of intermediate complexity CLIMBER-3α. The continental configurations comprise two palaeogeographic reconstructions for each of both snowball-Earth onsets as well as two idealised configurations with either uniformly dispersed continents or a single polar supercontinent. Orbital geometries are sampled as multiple different combinations of the parameters obliquity, eccentricity, and argument of perihelion. For volcanic eruptions, we differentiate between single globally homogeneous perturbations, single zonally resolved perturbations, and random sequences of globally homogeneous perturbations with realistic statistics. The CO2 threshold lies between 10 and 250 ppm for all simulations. While the thresholds for the idealised continental configurations differ by a factor of up to 19, the CO2 thresholds for the continental reconstructions differ by only 6 %–44 % relative to the lower thresholds. Changes in orbital geometry account for variations in the CO2 threshold of up to 30 % relative to the lowest threshold. The effects of volcanic perturbations largely depend on the orbital geometry and the corresponding structure of coexisting stable states. A very large peak reduction in net solar radiation of 20 or 30 W m−2 can shift the CO2 threshold by the same order of magnitude as or less than the orbital geometry. Exceptionally large eruptions of up to −40 W m−2 shift the threshold by up to 40 % for one orbital configuration. Eruptions near the Equator tend to, but do not always, cause larger shifts than eruptions at high latitudes. The effects of realistic eruption sequences are mostly determined by their largest events. In the presence of particularly intense small-magnitude volcanism, this effect can go beyond the ranges expected from single eruptions.
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Basley, Jérémy, Laurent Perret et Romain Mathis. « Structure of high Reynolds number boundary layers over cube canopies ». Journal of Fluid Mechanics 870 (10 mai 2019) : 460–91. http://dx.doi.org/10.1017/jfm.2019.274.
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The influence of a cube-based canopy on coherent structures of the flow was investigated in a high Reynolds number boundary layer (thickness $\unicode[STIX]{x1D6FF}\sim 30\,000$ wall units). Wind tunnel experiments were conducted considering wall configurations that represent three idealised urban terrains. Stereoscopic particle image velocimetry was employed using a large field of view in a streamwise–spanwise plane ($0.55\unicode[STIX]{x1D6FF}\times 0.5\unicode[STIX]{x1D6FF}$) combined to two-point hot-wire measurements. The analysis of the flow within the inertial layer highlights the independence of its characteristics from the wall configuration. The population of coherent structures is in agreement with that of smooth-wall boundary layers, i.e. consisting of large- and very-large-scale motions, sweeps and ejections, as well as smaller-scale vortical structures. The characteristics of vortices appear to be independent of the roughness configuration while their spatial distribution is closely linked to large meandering motions of the boundary layer. The canopy geometry only significantly impacts the wall-normal exchanges within the roughness sublayer. Bi-dimensional spectral analysis demonstrates that wall-normal velocity fluctuations are constrained by the presence of the canopy for the densest investigated configurations. This threshold in plan area density above which large scales from the overlying boundary layer can penetrate the roughness sublayer is consistent with the change of the flow regime reported in the literature and constitutes a major difference with flows over vegetation canopies.
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Siemes, Rutger, Trang Minh Duong, Pim Willemsen, Bas Borsje et Suzanne Hulscher. « ESTUARINE-WIDE SEDIMENT DYNAMICS UNDER HUMAN INTERVENTIONS AND CLIMATE CHANGE EFFECTS ; AN IDEALISED MODEL STUDY ». Coastal Engineering Proceedings, no 37 (1 septembre 2023) : 12. http://dx.doi.org/10.9753/icce.v37.sediment.12.
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Estuaries worldwide are under constant anthropogenic pressure. They are susceptible to climate change effects, from the sea (sea level rise, changing wave climate) and from the river-side (changing river discharge). Besides, estuaries are channelised and embanked to improve flood safety and to reclaim land, and channels are deepened to allow bigger ships to enter the ports. To optimise estuarine functions and sustainably prepare for future challenges, improved understanding of estuarine sediment dynamics after potential changes in the systems configuration and forcings is desired. This paper aims to assess the annual sediment dynamics of an estuary under a climate change effects, and how this is affected by human interventions.
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GRISOUARD, N., C. STAQUET et T. GERKEMA. « Generation of internal solitary waves in a pycnocline by an internal wave beam : a numerical study ». Journal of Fluid Mechanics 676 (1 avril 2011) : 491–513. http://dx.doi.org/10.1017/jfm.2011.61.
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Oceanic observations from western Europe and the south-western Indian ocean have provided evidence of the generation of internal solitary waves due to an internal tidal beam impinging on the pycnocline from below – a process referred to as ‘local generation’ (as opposed to the more direct generation over topography). Here we present the first direct numerical simulations of such a generation process with a fully nonlinear non-hydrostatic model for an idealised configuration. We show that, depending on the parameters, different modes can be excited and we provide examples of internal solitary waves as first, second and third modes, trapped in the pycnocline. A criterion for the selection of a particular mode is put forward, in terms of phase speeds. In addition, another simpler geometrical criterion is presented to explain the selection of modes in a more intuitive way. Finally, results are discussed and compared with the configuration of the Bay of Biscay.
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ASPDEN, A. J., M. S. DAY et J. B. BELL. « Turbulence–flame interactions in lean premixed hydrogen : transition to the distributed burning regime ». Journal of Fluid Mechanics 680 (31 mai 2011) : 287–320. http://dx.doi.org/10.1017/jfm.2011.164.
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The response of lean (ϕ ≤ 0.4) premixed hydrogen flames to maintained homogeneous isotropic turbulence is investigated using detailed numerical simulation in an idealised three-dimensional configuration over a range of Karlovitz numbers from 10 to 1562. In particular, a focus is placed on turbulence sufficiently intense that the flames can no longer be considered to be in the thin reaction burning regime. This transition to the so-called distributed burning regime is characterised through a number of diagnostics, and the relative roles of molecular and turbulent mixing processes are examined. The phenomenology and statistics of these flames are contrasted with a distributed thermonuclear flame from a related astrophysical study.
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Jemitola, P. O., J. Fielding et P. Stocking. « Joint fixity effect on structural design of a box wing aircraft ». Aeronautical Journal 116, no 1178 (avril 2012) : 363–72. http://dx.doi.org/10.1017/s0001924000005261.
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Abstract A computational study was performed to compare the stress distributions in finite element torsion box models of a box wing structure that result from employing four different wing/end fin joint fixities. All considered wings were trimmed in pitch. The joint fixities refer to the type of attachment that connects the tip of the fore and aft wings to the end fin. Using loads from a vortex lattice tool, the analysis determined the best wing-joint fixity of a statically loaded idealised box wing configuration by comparing the stress distributions resulting from the different wing joints in addition to other essential aerodynamic requirements. Analysis of the wing joint fixity indicates that the rigid joint is the most suitable.
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Martin, G. M., et R. C. Levine. « The influence of dynamic vegetation on the present-day simulation and future projections of the South Asian summer monsoon in the HadGEM2 family ». Earth System Dynamics 3, no 2 (28 novembre 2012) : 245–61. http://dx.doi.org/10.5194/esd-3-245-2012.
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Abstract. Various studies have shown the importance of Earth System feedbacks in the climate system and the necessity of including these in models used for making climate change projections. The HadGEM2 family of Met Office Unified Model configurations combines model components which facilitate the representation of many different processes within the climate system, including atmosphere, ocean and sea ice, and Earth System components including the terrestrial and oceanic carbon cycle and tropospheric chemistry. We examine the climatology of the Asian summer monsoon in present-day simulations and in idealised climate change experiments. Members of the HadGEM2 family are used, with a common physical framework (one of which includes tropospheric chemistry and an interactive terrestrial and oceanic carbon cycle), to investigate whether such components affect the way in which the monsoon changes. We focus particularly on the role of interactive vegetation in the simulations from these model configurations. Using an atmosphere-only HadGEM2 configuration, we investigate how the changes in land cover which result from the interaction between the dynamic vegetation and the model systematic rainfall biases affect the Asian summer monsoon, both in the present-day and in future climate projections. We demonstrate that the response of the dynamic vegetation to biases in regional climate, such as lack of rainfall over tropical dust-producing regions, can affect both the present-day simulation and the response to climate change forcing scenarios.
Thèses sur le sujet "Idealised configuration"
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Nasser, Antoine-Alexis. « Advancing the representation of flows along topography in z-coordinate ocean models ». Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS446.
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Les fonds marins exercent un contrôle majeur sur la circulation océanique. La représentation discrète de la topographie dans les modèles de circulation générale océanique (OGCM) géopotentiels crée des marches artificielles qui produisent des effets néfastes pour la simulation des courants. Cette thèse vise à établir des solutions adaptées pour résoudre les effets adverses des marches dans les OGCM. A partir de configurations idéalisées et en explorant le potentiel de la méthode de Pénalisation des Volumes de Brinkman (BVP), nous étudions la sensibilité des courants simulé aux frontières en marche d'escalier. Il est montré comment résoudre le 'spurious form drag' latéral (ou le 'staircase problem') mis en évidence par Adcroft et Marshall (1998). Les côtes (ainsi que les isobathes) représentées par des séries de marche deviennent lisses lorsqu'une condition miroir (glissement) est exactement appliquée sur l'écoulement à la côte. La formulation de la condition de glissement dans l'advection exprimé en 'flux-form' ou dans le tenseur visqueux symétrique produit dans le modèle du 'non-glissement' sur une topographie en marche d'escalier. Il est montré que la condition limite visqueuse doit changer le long des contours afin de simuler la rétroflexion du courants à un cape. Afin devenir insensible à la topographie en marche d'escalier, les modèles numériques devraient idéalement être physiquement convergés (c'est-à-dire que les caractéristiques principales de l'écoulement ne sont pas affectées par l'augmentation de la résolution spatiale en conservant les paramètres de viscosité et de friction constants). Il est montré que cette convergence peut être atteinte à une résolution plus faible en résolvant l'advection discrète des moments à l'aide de schémas utilisant un stencil élargi. On montre dans un overflow idéalisée l'impact de la résolution discrète de la quantité de mouvement sur la précision des écoulements le long des pentes en marche d'escalier. La méthode de BVP permet d'étaler l'interface terre-océan en définissant des cellules poreuses qui sont à moitié terre et à moitié océan. Étaler ainsi l'interface lisse les courants et réduit considérablement la diffusion numérique pendant la descente. Il est montré que la stabilité numérique de la méthode BVP peut être assurée en étalant suffisamment la frontière poreuse, et en ajustant de manière cohérente la perméabilité (friction dans les cellules poreuses). Les résultats soulignent le potentiel de la méthode BVP pour la meilleure représentation des courants le long des topographies dans les OGCMThe seafloor exerts a major control on ocean circulation. The discrete representation of marine topography in geopotential Ocean General Circulation Models (OGCMs) creates artificial steps that have adverse effects on the simulated circulation. This thesis aims at finding suitable ways to address the adverse effects of stepped topography in z-coordinate OGCMs. Using idealized configurations and exploring the potential of the Brinkman Volume Penalisation (BVP) method, we investigate the sensitivity of modelled currents to the presence of artificial steps along model boundaries. We first address the spurious lateral form drag (or textit{staircase problem}) highlighted by Adcroft and Marshall (1998). We show that staircase-like coastlines (and isobaths) behave as smooth boundaries when applying a textit{true} mirror condition on the boundary flow. The discrete implementation of free-slip using flux-form advection and a symmetric viscous stress tensor actually corresponds to no-slip along stepped topography. The choice of viscous boundary condition should vary with location to capture the retroflection of boundary currents at capes. To become insensitive to stepped topography, numerical models should ideally achieve physical convergence (i.e. the main characteristics of the flow are not affected by increasing spatial resolution while keeping viscous and frictional parameters constant). This convergence can be attained at lower resolution with a careful treatment of discrete momentum advection involving a large stencil. We highlight the impact of momentum advection schemes on the fidelity of simulated downslope currents within an idealised overflow configuration. The BVP method allows to spread the land-ocean interface, by introducing porous cells that are half-land half-ocean. We find that this spreading allows to smooth bottom currents and to reduce spurious mixing during downslope flow. The numerical stability of the BVP can be guaranteed by sufficient spreading of the boundary and by defining permeability (friction within porous cells) in a consistent way. The results underscore the potential of the BVP method to better represent flows along topography in OGCMs
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Smith, Robin Stuart. « Ocean circulation and climate dynamics under idealised continental configurations in a coupled ocean-atmosphere model ». Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402045.
Texte intégralLivres sur le sujet "Idealised configuration"
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Burns, E. Jane. Performing Courtliness. Sous la direction de Judith Bennett et Ruth Karras. Oxford University Press, 2013. http://dx.doi.org/10.1093/oxfordhb/9780199582174.013.021.
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Medieval courts can be understood as performance spaces in which courtly players, both historical composer/performers and their fictive characters, enacted complex and contradictory configurations of gender and power. From this perspective, courtly literature's constant reiteration of the established rules of love or codes of chivalric behavior might suggest not that those conventions are firmly in place but, on the contrary, that courtly literary texts assert a message of idealized and codified conduct that was actively resisted, challenged, and altered. Those alternative courtly performances were often enacted by women, whether by historical singer-composers, authors, and patrons or by a wide range of inscribed female characters in courtly texts.
Chapitres de livres sur le sujet "Idealised configuration"
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Maingonnat, Igor, Gilles Tissot et Noé Lahaye. « Correlated Structures in a Balanced Motion Interacting with an Internal Wave ». Dans Mathematics of Planet Earth, 207–22. Cham : Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-40094-0_9.
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AbstractCharacterizing the loss of coherence of an internal tide propagating through mesoscale turbulence has been a major challenge in oceanography, particularly due to its implications for the interpretation of satellite data. In this paper, we intend to study the correlations between a balanced motion and the incoherent part of a wave in an idealised configuration. We introduce a new modal decomposition technique, named broad-band proper orthogonal decomposition (BBPOD), which consists in performing a proper orthogonal decomposition (POD) on complex demodulated variables. After connecting BBPOD to the standard SPOD, we show that BBPOD, coupled with the extended POD technique enables us to associate the principal components of the incoherent field to the slow flow structures responsible of this loss of coherence through triadic interactions with the incident wave.
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Wagner, C., et R. Friedrich. « Turbulent flow in idealized Czochralski crystal growth configurations ». Dans Notes on Numerical Fluid Mechanics (NNFM), 367–80. Wiesbaden : Vieweg+Teubner Verlag, 1997. http://dx.doi.org/10.1007/978-3-322-86573-1_47.
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Totorean, Alin, Iuliana-Claudia Totorean, Sandor Bernad et Dan Gaita. « Numerical Investigation of an Idealized Overlapping Coronary Stents Configuration ». Dans Springer Proceedings in Physics, 251–58. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-54136-1_24.
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« Spray Combustion in Idealized Configurations : Parallel Drop Streams ». Dans Numerical Approaches to Combustion Modeling, 585–613. Washington DC : American Institute of Aeronautics and Astronautics, 1991. http://dx.doi.org/10.2514/5.9781600866081.0585.0613.
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Kastrup, Bernardo. « BRIEF INTRODUCTION TO, AND SUMMARY OF, ANALYTIC IDEALISM ». Dans METOD, 130–36. INION RAN, 2020. http://dx.doi.org/10.31249/metod/2020.10.06.
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I defend a modern, analytic formulation of metaphysical idealism, according to which the ground of existence is phenomenal consciousness. Everything else - I maintain - is reducible to configurations and patterns of excitation of consciousness.
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Giulini, Domenico. « Historical developments ». Dans Special Relativity, 5–37. Oxford University PressOxford, 2005. http://dx.doi.org/10.1093/oso/9780198567462.003.0002.
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Abstract In 1687 Isaac Newton’s (1643–1727)Philosophiae Naturalis Principia Mathematica, nowadays simply called ‘ThePrincipia’, appeared in print in London. In this monumental work, which in?uenced the physical discipline of mechanics like no other ever since, Newton laid down a physical theory in mathematical terms which allowed him to describe the motion of heavenly bodies within the very same formalism as terrestrial motions. Quite generally, Newton speaks of ‘bodies’, which eventually one has to think of as being built from infinitely small, infinitely tough, and never changing parts, which themselves are taken to require no further explanation. With this concept of ‘point masses’, as they are now called, Newtonian mechanics is able to reduce the motion of complex configurations of such point masses to their simple laws of motion, taking into account the forces between them. A simple though somewhat idealized hypo- thesis for such mutual forces leads to the notion of the ‘rigid body’, in which each point mass is held in constant position relative to the others, even if external forces are applied. The spatial configuration of such an ideal rigid body is fully characterized by just six numbers, three for the position of some preferred point of it, like e.g. the centre of mass, and three for the rotational freedom about this point.
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Ney, Alyssa. « Wave Function Realism in a Relativistic Setting ». Dans The World in the Wave Function, 133–65. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780190097714.003.0004.
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This chapter considers and responds to criticism that wave function realism is only plausible as an approach to the interpretation of nonrelativistic quantum mechanics and not relativistic quantum theories and quantum field theories. This critique gains traction as wave function realism has until now been formulated and defended solely within the context of idealized, nonrelativistic quantum mechanics. The chapter considers five such arguments and responds to each. An important lesson is that wave function realists should only adopt the wave-function-in-configuration-space picture as part of an interpretation of an idealized nonrelativistic quantum mechanics. More generally, the space the wave function inhabits will vary as the quantum theory the wave function realist is developing an interpretation of varies. The chapter develops a sketch of what wave function realism looks like in one relativistic context. It then discusses the issue of the interpretation of quantum theories in the limit of physical theorizing.
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Glass, Irvine I., et J. P. Sislian. « Boundary-Layer Effects ». Dans Nonstationary Flows and Shock Waves, 137–76. Oxford University PressOxford, 1994. http://dx.doi.org/10.1093/oso/9780198593881.003.0006.
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Abstract So far we have considered in some detail the wave system that might be produced in a simple shock tube for a perfect inviscid gas. The present chapter will endeavour to compare the real-flow situations encountered in simple shock tubes with the ideal-flow configurations derived in previous chapters. It will be found that viscosity and heat-transfer effects in the wall boundary layer of a shock tube modify the idealized wave system and the flow variables in the uniform states. The magnitude of these effects depends mainly on the strength of the incident shock wave, the initial conditions, the type of boundary layer, and the area and length of the shock-tube channel.
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Fhlainn, Sorcha Ní. « Contemporary Vampires ». Dans Twenty-First-Century Gothic, 102–16. Edinburgh University Press, 2019. http://dx.doi.org/10.3366/edinburgh/9781474440929.003.0008.
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This chapter tracks the trends of the contemporary vampire in the twenty-first century, from the vampire’s popular representation as an outsider and anti-hero, a carrier of a fatal plague, through to an idealised figure of desire in Gothic romance. Vampires in literature, film and television evidence their continued struggle as displaced figures caught between the ancient and the modern while remaining perfectly in tune with the zeitgeist. This chapter analyses the cultural assimilation and aggressive marketisation of the vampire narrative into separate strands for multiple audiences and generic configurations (from the Gothic romance to the action film), exposing the plurality of vampiric representation in the twenty-first century, including the tamed Gothic lover of the Twilight saga (2008–12), the ubiquitous and the synthetic nature of contemporary vampire society (HBO’s True Blood(2008–14)), and the persistent updating of popular twentieth-century vampire narratives, including Bram Stoker’s novel Dracula(1897), for a new century.
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Abrams, Aaron. « Braids ». Dans Office Hours with a Geometric Group Theorist. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691158662.003.0018.
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This chapter deals with mathematical braids, an idealized abstraction of the familiar hair and bread braids. In a mathematical braid, the “strings” remain separate at the ends rather than being fused together. Furthermore, a mathematical braid can have any number of braided strings and the braiding can occur in any pattern. This chapter gives different ways to think about mathematical braids and some of the basic theorems about them. It also describes several ways that braids relate to other parts of mathematics and science such as robotics, knot theory, and hyperplane arrangements. After providing an overview of some group theory relating to braids, the chapter considers configuration spaces that connect braid groups and topology as well as the concept of punctured disks. Finally, it presents an experiment for braiding the hair by first making a ponytail and then doing the braiding. The discussion includes exercises and research projects.
Actes de conférences sur le sujet "Idealised configuration"
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Pekris, Michael J., Gervas Franceschini et David R. H. Gillespie. « Effect of Geometric Changes in an Idealised Contacting Brush Seal Bristle Pack on Typical Key Performance Measures ». Dans ASME 2011 Turbo Expo : Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-46492.
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In an effort to reduce gas turbine specific fuel consumption and to increase specific thrust, advanced sealing technologies have been deployed for the purpose of secondary air flow management. One such technology, the brush seal, provides a more compliant seal and hence improved leakage performance over the legacy industry standard, the labyrinth seal. It is known that brush seal geometry has a strong effect on the loading, deformations, temperatures and flows in the bristle pack. There is limited understanding of the complex interactions between the geometric variables. This paper describes a methodology for the modelling of an idealised brush seal domain based on Computational Fluid Dynamics. Bristle pressure and force distributions, temperature distributions and tip contact forces are presented. This methodology is used to examine the sensitivity of these parameters to the geometric input variables for a contacting seal configuration, using a Design of Experiments approach. Inferences are drawn from the results to determine which of the geometric parameters are most influential in brush seal pack flow-induced behaviour, and the strength of the coupling between these parameters and the key performance indicators.
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Fransson, Jens H. M., Santhosh B. Mamidala, Bengt E. G. Fallenius, Hans Mårtensson et Fredrik Wallin. « An Experimental Setup for Idealised Studies on Transition to Turbulence on a Generic Compressor Outlet Guide Vane ». Dans ASME Turbo Expo 2018 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-76507.
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The understanding of flow phenomena in turbomachinery has come far with respect to three-dimensional flow patterns and pressure distributions. Much is due to improved measurements and a continuously evolving fidelity in computational fluid dynamics (CFD). Turbulence and transition in boundary layers are two classical areas where improvements in modeling are desired and where experimental validation is required. Apart from this, fundamental improvements in efficiency can be obtained by developing experimental resources where technologies affecting transition can be studied. The reduction in friction drag can be considerable if the transition to turbulence can be delayed. An experimental setup in an idealized configuration has been designed and built with the objective to study transition on a very large-scale guide vane profile at low speed. The purpose of the rig is to enable high quality fundamental studies of technologies to delay transition, but also to see how effects of manufacturing or other constraints may affect the boundary layer. In the present paper we report the first validation of the experimental setup, by comparing the first test results to CFD calculations performed during the rig design, i.e. no post-calculations with experimental data as input to the simulations have been done yet. The pressure distribution is in line with the design intent, which is a good indicator that the tunnel design is suitable for the intended purpose. At last we report some velocity measurements performed in the wake and we calculate the total drag based on the wake velocity deficit for various Reynolds numbers and with and without turbulence tripping tape. We illustrate that a two dimensional tripping around 7% of the chord from the leading edge can increase the total drag by 50% with respect to the reference case without tripping tape.
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Graves, Rick, et George Emanuel. « Parametric investigation of idealized hypersonic cruise configurations ». Dans 21st Atmospheric Flight Mechanics Conference. Reston, Virigina : American Institute of Aeronautics and Astronautics, 1996. http://dx.doi.org/10.2514/6.1996-3401.
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Bohn, Dieter, et Robert Krewinkel. « Conjugate Calculation of Effusion Cooling With Realistic Cooling Hole Geometries ». Dans ASME Turbo Expo 2009 : Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59082.
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Within Collaborative Research Center 561 “Thermally Highly Loaded, Porous and Cooled Multi-Layer Systems for Combined Cycle Power Plants” at RWTH Aachen University an effusion-cooled multi-layer plate configuration with seven staggered effusion cooling holes is investigated numerically by application of a 3-D in-house fluid flow and heat transfer solver, CHTflow. The effusion-cooling is realized by finest drilled holes with a diameter of 0.2 mm that are shaped in the region of the thermal barrier coating. The geometry of the cooling holes is not symmetrical, due to the manufacturing process. Furthermore, the inlet of the cooling holes in the plenum shows no sharp edges, which has a significant influence on the formation of the kidney-vortices within the cooling hole. The impact of this geometry on the cooling effectiveness has to be quantified prior to application. A hot gas Mach-number of 0.25 and blowing ratios of approximately 0.28 and 0.48 will be considered. The numerical grid contains the coolant supply (plenum), the solid body for the conjugate calculations and the main flow area on the plate. The form of the hole, especially that of the diffuser, leads to a skewered mass flow from the hole and a non-symmetric temperature distribution on the plate surface. Therefore, neither the flow field on the hot gas surface nor the temperature distribution can be compared with the usually investigated idealised hole geometries.
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Naqvi, Rehan, Olav Bolland, O̸yvind Brandvoll et Kaare Helle. « Chemical Looping Combustion-Analysis of Natural Gas Fired Power Cycles With Inherent CO2 Capture ». Dans ASME Turbo Expo 2004 : Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-53359.
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In this paper an alternative to so-called ‘oxy-fuel’ combustion has been evaluated. Chemical Looping Combustion (CLC) is an innovative concept of CO2 capture from combustion of fossil fuels in power plants. CLC is closely related to oxy-fuel combustion as the chemically bound oxygen reacts in a stoichiometric ratio with the fuel. In CLC, the overall combustion takes place in two steps. In a reduction reactor fuel is oxidised by the oxygen carrier i.e. the metal oxide MeO which is reduced to metal oxide with a lower oxidation number, Me. Me flows to an oxidation reactor where it is oxidised by oxygen in the air. In this way pure oxygen is supplied to fuel without using an energy intensive traditional air separation unit. This paper presents thermodynamic cycle analysis of a CLC-power plant. A steady-state model has been developed for the solid-gas reactions occurring in the reactor system. The model is applied to analyse the system under two configurations; a combined cycle and a conventional steam cycle. A turbine-cooling model has also been implemented to evaluate the turbine cooling penalty in the combined cycle configuration. Effects of exhaust recirculation for coking prevention and incomplete fuel conversion have also been investigated. Performance of the oxygen carrier has been idealised except for the degrees of reduction and oxidation. Energy needs for CO2 capture have properly been taken into account. The results show that an optimum efficiency of 49.7% can be achieved under given conditions with a CLC-combined cycle at zero emissions level. With turbine cooling, efficiency falls by 1.2% points under the same conditions. The CLC-steam cycle is capable of achieving 40.1% efficiency with zero emissions. The results show that CLC has high potential for power generation with inherent CO2 capture. This work will be useful in designing CLC systems after the reactor system has been analysed experimentally for long-term operations.
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Kerper, Dale, Christian M. Appendini, Henrik Kofoed-Hansen et Ida Bro̸ker. « Wave Setup in Inlets : Some Practical Considerations ». Dans ASME 2007 26th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2007. http://dx.doi.org/10.1115/omae2007-29292.
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For the determination maximum flood elevations, a number of components contributing to the total water level need to be considered. For instance, astronomical tide, storm surge, relative changes in mean sea level, wave setup, wave runup and wave splash. In this study, numerical models were used to evaluate under which conditions wave setup penetrates into an idealized inlet. A number of idealized inlet/lagoon configurations were tested. A coupled wave-current model was used to assess the static component of the wave setup. A Boussinesq wave model was used to assess the influence of the dynamic oscillating component of the wave setup. This study demonstrates how numerical modeling tools can be effectively used to assess how wave setup develops depending on a specific inlet configuration.
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Hodson, Joshua D., Robert E. Spall et Barton L. Smith. « RANS Predictions in an Idealized Lower-Plenum Model ». Dans 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/icone14-89222.
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The two-dimensional, unsteady, Reynolds-averaged Navier-Stokes equations have been solved for the flow across a row of confined cylinders with a pitch-to-diameter ratio of 1.7, a configuration which was designed to model a next generation nuclear plant lower-plenum. Four different turbulence models were used: k–ε, k–ω, v2–f, and differential Reynolds-stress transport. Comparisons with available experimental data were made for pressure losses, recirculation lengths, and mean velocity profiles. The results indicate that all models did a reasonable job of predicting the pressure loss coefficient. However, in terms of the mean velocities and recirculation length, the determination of which model performed best is not clear.
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Wagner, Claus, et Rainer Friedrich. « DIRECT NUMERICAL SIMULATION OF MOMENTUM AND HEAT TRANSPORT IN IDEALIZED CZOCHRALSKI CRYSTAL GROWTH CONFIGURATIONS ». Dans Third Symposium on Turbulence and Shear Flow Phenomena. Connecticut : Begellhouse, 2003. http://dx.doi.org/10.1615/tsfp3.1310.
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Véron, Philippe, et Jean-Claude Léon. « Geometric Tools Dedicated to the Adaption and Idealization of 3D Models for F.E. Analysis ». Dans ASME 1997 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/detc97/cie-4445.
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Abstract Geometric adaptions and idealizations of 3D models for F.E. analysis purposes are often necessary. Geometric tools are proposed to partly automatize shape adaptions and idealizations of polyhedral models. The simplification process is monitored using error zones attached to each polyhedron vertex. Their dimension may be either set by the designer, by an a posteriori or by an a priori mechanical mesh adaption process. Such an approach allows to process various polyhedral models characterized by general and complex shapes. A classification of nodes and edges is carried out to apply a specific node removal operator in accordance with the local geometric configuration around a node. Moreover, specific criteria are used to select the best candidate node for removal. Also, additional operators have been developed to process particular configurations and produce the final idealized model. During this geometric idealization process, the shape restitution of the part is maintained through an inheritance process of the error zones. Topological changes as well as the coherence of the non-manifold geometric model are managed using specific criteria to produce acceptable approximations of idealized geometries.
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Shirazi-Adl, A., et M. Parnianpour. « On an Idealized Wrapping Loading of the Human Spine ». Dans ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0478.
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Abstract The kinetic redundancy of the complex human spinal system presents a rather insurmountable obstacle in estimating the activation patterns and passive-active load sharing. A plausible hypothesis is that the spinal posture, at a given task and load level, is so adjusted as to maintain equilibrium and a sufficient margin of safety against instability while minimizing the need for muscle exertion. Our recent in vivo and model studies support the importance of the pelvic tilt and lumbar curvature in mechanics of the human spine (Shirazi-Adl and Parnianpour, 1996, 1999). In view of very low compression load-carrying capacity (i.e., stability) of the passive ligamentous spine, attempts have been made to investigate optimal path of applied compression loading that could both stabilize the passive system and result in lower stresses and higher margin of safety against tissue failure (Aspeden, 1989; Gracovetsky et al., 1989). Recent in vitro experimental and model studies on the lumbar spine has demonstrated that the passive ligamentous lumbar spine with no musculature is stable under compression loads that remain perpendicular to disc mid-height planes (i.e., wrapping or continuous follower loads) (Patwardhan et al., 1998; Shirazi-Adl and Parnianpour, 1998). In this work, the response of the lumbar and thoracolumbar spine under wrapping compression loads is investigated in order to study the stabilizing effect of this idealized loading configuration as well as its effect on internal tissue-level stress/strain values.
Rapports d'organisations sur le sujet "Idealised configuration"
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Horrigan, Timothy J. Configuration and the Effectiveness of Air Defense Systems in Simplified, Idealized Combat Situations - A Preliminary Examination,. Fort Belvoir, VA : Defense Technical Information Center, juin 1990. http://dx.doi.org/10.21236/ada301576.
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