Bibliographies thématiques / Numerical slar radiation model

Littérature scientifique sur le sujet « Numerical slar radiation model »

Auteur : Grafiati

Publié le 10 mars 2023

Mis à jour le 11 mars 2023

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Articles de revues sur le sujet "Numerical slar radiation model"

Wang, Jian Ping, Bo Chen, Jin Zheng et Peng Yun Li. « Evaluation on the Thermal Stresses of a Concrete Slab under Solar Radiation ». Advanced Materials Research 671-674 (mars 2013) : 2542–46. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.2542.

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The time-varying temperature field and stress distribution of a concrete roof slab is actively investigated in this study with the aiding of the commercial package ANSYS. Fine finite element model of the concrete slab is constructed and different boundary conditions are applied to obtain the temperature distribution within the slab. The solar radiation model is utilized to estimate the solar radiation received by the slab and the shelter effects are also taken into consideration. The numerical models can successfully predict the structural temperature gradient and thermal stress distribution at different time. The made observations indicate that the simulated temperature variation of the concrete slab based on the solar radiation model agrees well with measurement results. It is seen that the numerical models can successfully predict the structural time-varying thermal effects.

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Wang, Jian Ping, Bo Chen, Jin Zheng et Peng Yun Li. « Analysis on the Daily Temperature Variation of a Concrete Slab under Environmental Effects ». Advanced Materials Research 671-674 (mars 2013) : 2530–34. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.2530.

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The dynamic temperature field of a concrete slab is actively studied in this study with the aiding of the commercial package ANSYS. Fine finite element model of the concrete slab is constructed and different boundary conditions are applied to obtain the temperature distribution within the slab with the aid of the commercial software package ANSYS. The solar radiation model is utilized to estimate the solar radiation received by the slab and the shelter effects are also taken into consideration. The numerical models can successfully predict the structural temperature at different time. The made observations demonstrate that the simulated temperature variation of the concrete slab based on the solar radiation model agrees well with measurement results. It is seen that the numerical models can successfully predict the structural temperature field at different time. The methodology employed in the paper can be applied to other concrete structures as well.

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Veselý, Jakub, et Vít Šmilauer. « THERMO-MECHANICAL MODEL FOR CONCRETE PAVEMENT ». Acta Polytechnica CTU Proceedings 30 (22 avril 2021) : 121–25. http://dx.doi.org/10.14311/app.2021.30.0121.

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This paper describes a numerical thermo-mechanical model for concrete pavement, implemented in OOFEM software. The thermal part is a heat transfer problem with appropriate initial and boundary conditions (sun irradiation, radiation and convection), calibrated from experimental data. Heat release from cement hydration is also included, calibrated for commonly used cements to demonstrate the difference that can be achieved with the binder selection. The mechanical part of the problem is composed of a 3D elastic concrete slab, subsoil Winkler-Pasternak elements and 1D interface elements, allowing separation in tension. The Winkler-Pasternak constants C1 and C2 were firstly determined from TP170 document and refined later from static load tests on the highway. The model validates well temperature field, static load test and provide several useful insight such as feasible time for summer casting, stress/strain fields and slab separation from the base.

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Cherkaoui, M., J. L. Dufresne, R. Fournier, J. Y. Grandpeix et A. Lahellec. « Monte Carlo Simulation of Radiation in Gases With a Narrow-Band Model and a Net-Exchange Formulation ». Journal of Heat Transfer 118, n^o 2 (1 mai 1996) : 401–7. http://dx.doi.org/10.1115/1.2825858.

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The Monte Carlo method is used for simulation of radiative heat transfers in nongray gases. The proposed procedure is based on a Net-Exchange Formulation (NEF). Such a formulation provides an efficient way of systematically fulfilling the reciprocity principle, which avoids some of the major problems usually associated with the Monte Carlo method: Numerical efficiency becomes independent of optical thickness, strongly nonuniform grid sizes can be used with no increase in computation time, and configurations with small temperature differences can be addressed with very good accuracy. The Exchange Monte Carlo Method (EMCM) is detailed for a one-dimensional slab with diffusely or specularly reflecting surfaces.

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Heping, Tan, B. Maestre et M. Lallemand. « Transient and Steady-State Combined Heat Transfer in Semi-Transparent Materials Subjected to a Pulse or a Step Irradiation ». Journal of Heat Transfer 113, n^o 1 (1 février 1991) : 166–73. http://dx.doi.org/10.1115/1.2910521.

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A numerical analysis based on the finite difference scheme and Hottel’s zonal method generalized by the ray tracing method is carried out to treat the one-dimensional transient and steady-state combined radiative-conductive heat transfer in non-gray Semi-Transparent Materials (STM), especially glasses, subjected to an external pulse or a step of irradiation. Coupling problems are studied for two optical boundary conditions: opaque and vitreous interfaces with specular reflections. The influence of slab thickness, spectral properties of the STM, wavelength of the incident radiation, and diffusivity coefficient are examined. It is pointed out that the application of the laser flash method in thermal metrology may give irrelevant results if the basic heat transfer model is not able to take into account radiative-conductive coupling phenomena. The effect of semi-transparency on the steady-state temperature distribution is also examined for materials ranging from fully opaque to fully transparent.

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Rybin, Oleg, et Sergey Shulga. « Feedback magnetization of ultra-low index irradiative structure ». Modern Physics Letters B 29, n^o 29 (25 octobre 2015) : 1550179. http://dx.doi.org/10.1142/s0217984915501791.

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Ultra-low refractive index irradiative structure is considered. The structure consists of a patch antenna with the metamaterial slab located on top of the antenna, as superstrate. In this study, ultra-low index phenomenon of the irradiative system is associated with improving the directivity of the patch antenna by putting the metamaterial slab on top of the antenna. The last phenomenon, in turn, is associated with the feedback partial magnetization of Iron inclusions of the slab caused by the radiation from the antenna. Mathematical model for evaluating the complex effective relative permittivity of the irradiative structure is developed. Numerical calculations for complex effective relative permittivity of the irradiative structure and real part of the complex effective relative permeability of the metamaterial slab are done in the study.

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Godfrey, Christopher M., et David J. Stensrud. « Soil Temperature and Moisture Errors in Operational Eta Model Analyses ». Journal of Hydrometeorology 9, n^o 3 (1 juin 2008) : 367–87. http://dx.doi.org/10.1175/2007jhm942.1.

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Abstract Proper partitioning of the surface heat fluxes that drive the evolution of the planetary boundary layer in numerical weather prediction models requires an accurate specification of the initial state of the land surface. The National Centers for Environmental Prediction (NCEP) operational Eta Model is used to produce land surface analyses by continuously cycling soil temperature and moisture fields. These fields previously evolved only in response to radiation budget constraints and modeled precipitation, but NCEP recently upgraded the self-cycling process so that soil fields respond instead to the radiation budget and observed precipitation. A comparison of 0000 and 1200 UTC Eta Model analyses of soil temperature and moisture at several soil depths with observations from the Oklahoma Mesonet during 2004 and 2005 shows that there are strong biases in soil temperature and a severe underestimation of soil moisture at all depths. After the change to a new assimilation scheme, there is notable improvement in the magnitude of the analyzed soil moisture fields, although a strong dry bias persists in the soil moisture field. A simple one-layer slab soil model quantifies the effect of such soil moisture errors on the diurnal cycle of soil temperature and reveals that these soil moisture errors alone may account for only 1.6°C increases in predicted maximum soil temperatures during the day and temperature reductions of the same magnitude at night. The much larger remaining soil temperature errors possibly stem from documented problems with the solar radiation and longwave parameterizations within the Eta Model.

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Zhang, Xun, Xiaozhen Li, Zhipeng Wen et Yu Zhao. « Numerical and experimental investigation into the mid- and high-frequency vibration behavior of a concrete box girder bridge induced by high-speed trains ». Journal of Vibration and Control 24, n^o 23 (14 mars 2018) : 5597–609. http://dx.doi.org/10.1177/1077546318761442.

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Concrete box girder bridges exhibit mid- and high-frequency (> 20 Hz) dynamic responses due to train excitations, which result in problems of noise radiation and track deterioration. This study presents a numerical model for box girder vibration prediction. Significant attention is focused on the mid- and high-frequency responses via introduction of a detailed track/bridge subsystem model. A hammer impact test was used to determine the model parameters. The model was then validated using a homologation test. The results show that the wheel/rail force and box girder mobility are the two principal factors that influence box girder vibration spectral characteristics and amplitudes. The box girder responses at cross-sections with similar dynamic characteristics vary little, as they increase moderately with the train speed. The application of a fastening system with low stiffness and high damping can effectively reduce box girder vibration. However, the elastic modulus and damping of the cement–asphalt mortar, and the thickness of the track slab and bearing base exert the smallest influences on the vibrations. The box girder slab thickness should be designed appropriately because its dynamic behavior is closely associated with the slab characteristics.

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Liu, Xiao, Nan Zhang, Qikai Sun, Kunpeng Wang et Zhaozhi Wu. « Parametric Analysis of Structural Noise of Steel-Concrete Composite Slab Beams ». Shock and Vibration 2022 (7 mars 2022) : 1–10. http://dx.doi.org/10.1155/2022/3176793.

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In this study, the vibration acceleration and radiation structure noise in specific points, 30 cm away from the center surface of each plate of the concrete deck, web, and flange of the steel beam, are measured via the hammering test. The test is conducted on the middle concrete deck of an 8.5 m steel-concrete composite slab beam. The accuracy of the numerical model is then carefully justified. The influence of the number of shear studs, spacing, and arrangement of ribs on the concerning results is methodically examined and discussed by employing the numerical model. In the center frequency of 10–1000 Hz, the total sound power level of the structure can be lessened by improving the concrete deck thickness as well as the number of shear studs. The reduction of the rib spacing can effectively lessen the sound power level as well. The noise reduction of the plate with rib arrangement in the midspan zone is more influential than the case with uniform layout in the whole span.

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Li, Yang, et Hao Ling. « NUMERICAL MODELING AND MECHANISM ANALYSIS OF VHF WAVE PROPAGATION IN FORESTED ENVIRONMENTS USING THE EQUIVALENT SLAB MODEL ». Progress In Electromagnetics Research 91 (2009) : 17–34. http://dx.doi.org/10.2528/pier09012306.

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Thèses sur le sujet "Numerical slar radiation model"

Maggiorano, Anna. « Solar radiation penetration in biogeochemical model of the coastal ocean. Numerical experiments ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13542/.

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This study focus on the analysis of different algorithms used to describe underwater light attenuation in the coastal ocean and their impact on primary production processes in a numerical coupled model of the marine biogeochemical dynamics. Light parameterizations (novel and literature based) were embedded into the BFM-POM one dimensional modelling system. Results indicated that better representation of the light vertical profiles are obtained with a double exponential formulation, particu- larly when parameterized on the basis of extensive in situ data. Better representation of the light environment impacted positively on the quality of the marine ecosystem biogeochemical dynamics simulation.

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Fan, Xiaobing 1960. « Numerical model for calculating the ultrasonic power deposition in layered medium ». Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278188.

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An improved numerical model for calculating the ultrasonic power deposition in layered medium was developed and experimentally verified. The new model takes into account the ultrasound wave reflection and refraction at irregular tissue interfaces thereby providing improved accuracy in ultrasound hyperthermia treatment planning. The model was compared with a simplified model to evaluate when the tissue interfaces could be ignored in the hyperthermia treatment planning and evaluation. The effects of variations in water and tissue temperatures, the fat layer thicknesses, the bone-tissue interface, and the beam entrance angles were also investigated to establish guidelines for treatment execution. It was found that in most cases the effects of the soft tissue interfaces can be ignored. However, in some instances the acoustic focus may be shifted several millimeters off axis in layered medium. This is important when sharply focused transducers are used for ultrasound surgery or under the condition of pulsed, high temperature hyperthermia treatments.

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Stancil, Maurice Marcus. « Creation and Experimental Validation of a Numerical Model of a Michelson Interferometer ». Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/74957.

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The study whose results are presented here was carried out in support of an ongoing larger effort to investigate and understand the impact of coherence and polarization on the performance of instruments intended to monitor the Earth's radiant energy budget. The visibility of fringes produced by a Michelson interferometer is known to be sensitive to the degree to which the incident light beam is monochromatic. Therefore, the Michelson interferometer has significant potential as a tool for quantifying the degree of temporal coherence of a quasi-monochromatic light beam. Simulation of the performance of an optical instrument using the Monte-Carlo ray-trace (MCRT) method has been shown to be an efficient method for transferring knowledge of the coherence state of a beam of light from one instrument to another. The goal of the effort reported here is to create and experimentally validate an MCRT model for the optical performance of a Michelson interferometer. The effort is motivated by the need to consolidate the knowledge and skills of the investigator in the realm of physical optics, and by the need to make a useful analytical tool available to other investigators in the larger effort.
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Mahee, Durude. « Numerical Simulation and Graphical Illustration of Ionization by Charged Particles as a Tool toward Understanding Biological Effects of Ionizing Radiation ». University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535381068931831.

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Sang, W. M. « A search for the Standard Model Higgs boson using the OPAL detector at LEP ». Thesis, Brunel University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340840.

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Wang, Ying. « Numerical study of a confined thermal plume at different flow regimes under the influence of gas radiation ». Thesis, La Rochelle, 2020. http://www.theses.fr/2020LAROS005.

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Ce travail est une étude numérique d’un panache thermique confiné en présence de rayonnement de gaz. Le panache est généré par une source de chaleur linéaire immergée dans une cavité cubique remplie d’air. Le but principal est de caractériser l’évolution du panache tout au long de sa transition depuis le régime stationnaire jusqu’à la turbulence, et d’explorer les effets du rayonnement de gaz sur la stabilité, les transferts de chaleur, les champs thermiques et cinétiques du panache.Les simulations numériques DNS sont effectuées pour des nombres de Rayleigh de 106 à 109 avec un logiciel CFD de volumes finis couplé à un module de transferts radiatifs. La situation de convection pure est étudiée en premier lieu pour caractériser les champs thermiques et cinétiques du panache dans différents régimes d’écoulement. Ensuite, le couplage convection-rayonnement est introduit en considérant un gaz gris ou un gaz réel (mélange air – vapeur d’eau). Les effets de l’épaisseur optique sont analysés en détail pour le modèle de gaz gris. Les résultats montrent que le rayonnement stabilise le panache et retarde la transition à l’instationnarité. Le rayonnement homogénéise également le champ thermique et réduit l’extension spatiale du panache. Cependant, l’effet sur le champ cinétique dépend du régime d’écoulement. A l’état stationnaire, le rayonnement de gaz diminue la circulation globale tandis que pour les états transitoires et turbulents, il augmente la dynamique de l’écoulement pour des milieux optiques minces. Ces tendances générales sont confirmées pour le mélange de gaz réel par une étude paramétrique de la concentration de vapeur d’eau et de la température de référence
This work presents a numerical investigation of a confined thermal plume under the influence of gas radiation. Plumeflow is generated by a linear heat source of constant power density immersed in a cubic cavity. The main aim of this thesis is to characterize the evolution of the plume throughout its transition from steady-state to turbulent regime, and to explore the gas radiation effects on flow stability, heat transfers, thermal and kinetic fields of the plume. DNS numerical simulations are performed over a Rayleigh number range from 106 to 109 by applying a finite volume CFD software coupled to a module for radiative heat transfer calculations. The pure convective situation is studied first to characterize the thermal and kinetic fields of the plume in different flow regimes. Next, the convection-radiation coupling is introduced by considering either gray gas or real gas (air - H2O mixture) media. The effects of optical thickness are analyzed in details for gray gas model. Results show that gas radiation stabilizes the plume flow and delays the onset of unsteadiness. Gas radiation also homogenizes the thermal field and reduces its spatial spreading. However, radiation effect on the kinetic field depends on the flow state. For steady state, gas radiation decreases the global flow circulation while for transient and turbulent states, it enhances the flow dynamics in optically thin medium.These general trends of radiation are also confirmed in real gas mixture through a parametric study of water vapor concentration and reference temperature

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Schomburg, Annika [Verfasser]. « Improving the simulation of small-scale variability in radiation and land-surface parameterizations in a mesoscale numerical weather prediction model / Annika Schomburg. Mathematisch-Naturwissenschaftliche Fakultät ». Bonn : Universitäts- und Landesbibliothek Bonn, 2011. http://d-nb.info/1016198094/34.

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Bhardwaj, Shubhendu. « Hybrid Numerical Models for Fast Design of Terahertz Plasmonic Devices ». The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500336630858748.

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Lu, Xijia. « An Applied Numerical Simulation of Entrained-Flow Coal Gasification with Improved Sub-models ». ScholarWorks@UNO, 2013. http://scholarworks.uno.edu/td/1696.

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The United States holds the world's largest estimated reserves of coal and is also a net exporter of it. Coal gasification provides a cleaner way to utilize coal than directly burning it. Gasification is an incomplete oxidation process that converts various carbon-based feedstocks into clean synthetic gas (syngas), which can be used to produce electricity and mechanical power with significantly reduced emissions. Syngas can also be used as feedstock for making chemicals and various materials. A Computational Fluid Dynamics (CFD) scheme has been used to simulate the gasification process for many years. However, many sub-models still need to be developed and improved. The objective of this study is to use the improved CFD modeling to understand the thermal-flow behavior and the gasification process and to provide guidance in the design of more efficient and cheaper gasifiers. Fundamental research has been conducted to improve the gasification sub-models associated with the volatile thermal cracking, water-gas-shift (WGS) reaction, radiation effect, low-rank-coal gasification, coal to synthetic-natural-gas (SNG), and ash deposition mechanisms. The improved volatile thermal cracking model includes H2S and COS contents. A new empirical WGS reaction model is developed by matching the result with experimental data. A new coal demoisturization model is developed for evaporating the inherent moisture inside the coal particles during low-rank-coal gasification. An ash deposition model has also been developed. Moreover, the effect of different radiation models on the simulated result has been investigated, and the appropriate models are recommended. Some improved model tests are performed to help modify an industrial entrained-flow gasifier. A two-stage oxygen feeding scheme and a unique water quench design are investigated. For the two-stage oxygen feeding design, both experimental data and CFD predictions verify that it is feasible to reduce the peak temperature and achieve a more uniform temperature distribution in the gasifier by controlling the injection scheme without changing the composition and production rate of the syngas. Furthermore, the CFD simulation can acceptably approximate the thermal-flow and reaction behaviors in the coal gasification process, which can then be used as a preliminary screening tool for improving existing gasifiers’ performance and designing new gasifiers.

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Loussouarn, Thomas. « Maîtrise de la thermique des fours de maintien en fonderie ». Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0105.

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Les fours de maintien à induction sous vide sont utilisés pour la fabrication d'aubes de turbine à l'aide du procédé de fonderie à cire perdue. La maîtrise de la thermique de ce dernier est primordiale afin d'assurer la qualité de la production. Ce travail est composé de 3 grandes parties : la modélisation détaillée du four, la modélisation réduite et l'expérience. Un four axisymétrique et sa charge ont été modélisés numériquement à l'aide des logiciels FlexPDE et COMSOL Multiphysics. Ces modèles utilisent en entrée la puissance consommée par les inducteurs et fournissent en sortie la température en tout point du module de chauffe et de la charge. Les modèles réduits étudiés sont des modèles physiques dit convolutifs (enthalpique (0D), analytique de dimension 1 (1D)) et paramétrique de type AutoRégressifs avec variables eXogènes (ARX). Les modèles ARX ont été comparés aux modèles convolutifs (procédures d'identification, puis de validation, de modèles). L'objectif est d'accéder à des températures en certains points du four sans présence d'un capteur physique local (capteur virtuel). Les modélisations détaillées et réduites ont été comparées à des expériences réalisées sur four de production. Cette dernière partie n'est pas décrite dans ce mémoire
Vacuum holding induction furnaces are used for the manufacturing of turbine blades by loss wax foundry process. Heat transfer control in a holding furnace is crucial to ensure the quality of manufacturing. This work has 3 major parts, which are the detailed modelling, reduced modelling and experiments. An axyisymmetric furnace and its load have been numerically modelled using FlexPDE and COMSOL Multiphysics, finite element codes. Modelling takes as inputs the electric power consumed by inductors and gives the temperature field in the heating module. The studied reduced models are phyisical convolutive models (enthalpic (0D), 1 dimension analytical (1D)) and parametric like AutoRegressive with eXogeneous inputs (ARX). ARX models have been compared to convolutive models (identification, validation). The goal is to get temperatures in the heating module without local presence of physical sensors (virtual sensor). Detailed and reduced models have been compared to experiments on the furnace. This last part is not described in this document

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Livres sur le sujet "Numerical slar radiation model"

Xue, Yongkang, Yaoming Ma et Qian Li. Land–Climate Interaction Over the Tibetan Plateau. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.592.

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The Tibetan Plateau (TP) is the largest and highest plateau on Earth. Due to its elevation, it receives much more downward shortwave radiation than other areas, which results in very strong diurnal and seasonal changes of the surface energy components and other meteorological variables, such as surface temperature and the convective atmospheric boundary layer. With such unique land process conditions on a distinct geomorphic unit, the TP has been identified as having the strongest land/atmosphere interactions in the mid-latitudes.Three major TP land/atmosphere interaction issues are presented in this article: (1) Scientists have long been aware of the role of the TP in atmospheric circulation. The view that the TP’s thermal and dynamic forcing drives the Asian monsoon has been prevalent in the literature for decades. In addition to the TP’s topographic effect, diagnostic and modeling studies have shown that the TP provides a huge, elevated heat source to the middle troposphere, and that the sensible heat pump plays a major role in the regional climate and in the formation of the Asian monsoon. Recent modeling studies, however, suggest that the south and west slopes of the Himalayas produce a strong monsoon by insulating warm and moist tropical air from the cold and dry extratropics, so the TP heat source cannot be considered as a factor for driving the Indian monsoon. The climate models’ shortcomings have been speculated to cause the discrepancies/controversies in the modeling results in this aspect. (2) The TP snow cover and Asian monsoon relationship is considered as another hot topic in TP land/atmosphere interaction studies and was proposed as early as 1884. Using ground measurements and remote sensing data available since the 1970s, a number of studies have confirmed the empirical relationship between TP snow cover and the Asian monsoon, albeit sometimes with different signs. Sensitivity studies using numerical modeling have also demonstrated the effects of snow on the monsoon but were normally tested with specified extreme snow cover conditions. There are also controversies regarding the possible mechanisms through which snow affects the monsoon. Currently, snow is no longer a factor in the statistic prediction model for the Indian monsoon prediction in the Indian Meteorological Department. These controversial issues indicate the necessity of having measurements that are more comprehensive over the TP to better understand the nature of the TP land/atmosphere interactions and evaluate the model-produced results. (3) The TP is one of the major areas in China greatly affected by land degradation due to both natural processes and anthropogenic activities. Preliminary modeling studies have been conducted to assess its possible impact on climate and regional hydrology. Assessments using global and regional models with more realistic TP land degradation data are imperative.Due to high elevation and harsh climate conditions, measurements over the TP used to be sparse. Fortunately, since the 1990s, state-of-the-art observational long-term station networks in the TP and neighboring regions have been established. Four large field experiments since 1996, among many observational activities, are presented in this article. These experiments should greatly help further research on TP land/atmosphere interactions.

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Chapitres de livres sur le sujet "Numerical slar radiation model"

Masunaga, Hirohiko, S. Inutsuka et S. M. Miyama. « A Radiation Hydrodynamical Model for Protostellar Collapse ». Dans Numerical Astrophysics, 169–70. Dordrecht : Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4780-4_52.

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Zhang, Xianying, David J. Thompson et Giacomo Squicciarini. « A New Model for the Prediction of Track Sound Radiation ». Dans Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 709–21. Cham : Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-73411-8_56.

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Brabec, Marek, Krystof Eben, Emil Pelikan, Pavel Krc, Jaroslav Resler et Pavel Jurus. « Statistical Modeling for Improvement of Numerical-Model-Based Solar Radiation Forecasts ». Dans Proceedings of the Third International Afro-European Conference for Industrial Advancement — AECIA 2016, 248–57. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-60834-1_26.

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Liu, J., M. Zeng, A. H. Shi, R. L. Zhang, J. L. Le et Z. H. Qu. « Numerical calculation of visible spectral radiation of sphere model in ballistic range ». Dans Shock Waves, 233–38. Berlin, Heidelberg : Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/978-3-540-27009-6_33.

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Ortega-Quijano, N., F. Fanjul-Vélez, I. Salas-García et J. L. Arce-Diego. « Numerical Modeling of Optical Radiation Propagation in a Realistic Model of Adult Human Head ». Dans IFMBE Proceedings, 1679–82. Cham : Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-00846-2_414.

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Wang, Jinpeng, Lizhen Wang, Mingyu Xie et Zhijun Tu. « A Novel Plume Radiation Model for Analyzing Thruster Plume Impact on IRES Based on Numerical Simulation ». Dans Lecture Notes in Electrical Engineering, 723–31. Singapore : Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-33-4102-9_87.

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Rao, Gandikota V., et James O’Sullivan. « A Review of some Recent Radiation Fog Prediction Studies and the Results of Integrating a Simple Numerical Model to Predict Radiation Fog over Brunei ». Dans Air Quality, 239–50. Basel : Birkhäuser Basel, 2003. http://dx.doi.org/10.1007/978-3-0348-7970-5_14.

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Alok, Praveen, Sai Charan Teja Javvadi, Pavan Kumar Konchada et G. Raam Dheep. « Numerical Simulation of a Single-Pass Parallel Flow Solar Air Heater with Circular Fins Using S2S Radiation Model ». Dans Lecture Notes in Mechanical Engineering, 101–11. Singapore : Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-7831-1_10.

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Di Napoli, Claudia, Alessandro Messeri, Martin Novák, João Rio, Joanna Wieczorek, Marco Morabito, Pedro Silva, Alfonso Crisci et Florian Pappenberger. « The Universal Thermal Climate Index as an Operational Forecasting Tool of Human Biometeorological Conditions in Europe ». Dans Applications of the Universal Thermal Climate Index UTCI in Biometeorology, 193–208. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-76716-7_10.

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AbstractIn operational weather forecasting standard environmental parameters, such as air temperature and humidity, are traditionally used to predict thermal conditions in the future. These parameters, however, are not enough to describe the thermal stress induced by the outdoor environment to the human body as they neglect the human heat budget and personal characteristics (e.g. clothing). The Universal Thermal Climate Index (UTCI) overcomes these limitations by using an advanced thermo-physiological model coupled with a state-of-the-art clothing model. Several systems have been recently developed to operationally forecast human biometeorological conditions via the UTCI, i.e. by computing UTCI from the forecasts of air temperature, humidity, wind speed and radiation as provided by numerical weather prediction models. Here we describe the UTCI-based forecasting systems developed in Czech Republic, Italy, Poland, Portugal and at the pan-European scale. Their characteristics are illustrated and their potential as warning systems for thermal hazards discussed.

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LOVISOLO, G., M. PEDRINI, G. PERRETTI, A. CIVIDALLI, F. MAURO et P. TOGNOLATTI. « A PROCEDURE TO CONTROL A PROSTATIC ENDOCAVITARY HYPERTERMIA TREATMENT BY USING A NUMERICAL MODEL ». Dans Radiation Research : A Twentieth-century Perspective, 290. Elsevier, 1991. http://dx.doi.org/10.1016/b978-0-12-168561-4.50986-0.

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Actes de conférences sur le sujet "Numerical slar radiation model"

Rahmanpour, Morteza, Reza Ebrahimi et Mehrzad Shams. « Numerical Modeling of Radiative and Reactive Flow Field Around a Blunt Body at Hypersonic Regimes ». Dans 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-22028.

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A numerical method for calculation of strong radiation for two-dimensional reactive air flow field is developed. The governing equations are taken to be two dimensional, compressible Reynolds-average Navier-Stokes and species transport equations. Also, radiation heat flux in energy equation is evaluated using a model of discrete ordinate method. The model used S4 approximation to reduce the governing system of integro-differential equations to coupled set of partial differential equations. A multiband model is used to construct absorption coefficients. Tangent slab approximation is assumed to determine the characteristic parameters needed in the Discrete Ordinates Method. The turbulent diffusion and heat fluxes are modeled by Baldwin and Lomax method. The flow solution is obtained with a fully implicit time marching method. A thermochemical nonequilibrium formulation appropriate to hypersonic transitional flow of air is presented. The method is compared with existing experimental results and good agreement is observed.

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Zhang, Cheng. « Numerical Modeling of Coal Gasification in an Entrained-Flow Gasifier ». Dans ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-88481.

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The gasification technology has been applied in Integrated Gasification Combined Cycle (IGCC) plants for the production of power, and polygeneration plants for the production of industrial chemicals, fuels, hydrogen, and power. The major advantages of the gasification technology are its potential for feed-stock flexibility, product flexibility, and relative simple removal of harmful emissions of nitrogen oxides (NOx), sulfur oxides (SOx), and CO2. Entrained-flow gasifiers are the preferred gasifier design for future deployment due to their high carbon conversion, high efficiency and high syngas purity. Current entrained-flow gasifier designs still have serious problems such as injector failure, refractory failure, slag blockages, downstream fouling and poisoning, poor space efficiency, and lack of dynamic feedstock flexibility. To better understand the entrained-flow gasification process, we performed steady Reynolds-averaged Navier-Stokes (RANS) modeling of the laboratory-scale gasifier developed at Brigham Young University (BYU) using ANSYS Fluent. An Eulerian approach is used to describe the gas phase, and a Lagrangian approach is used to describe the particle phase. The interactions between the gas phase and particle phase is modeled using the particle-source-in-cell approach. Turbulence is modeled using the shear-stress transport (SST) k–ω model. Turbulent particle dispersion is taken into account by using the discrete random walk model. Devolatilization is modeled using a version of the chemical percolation devolatilization (CPD) model, and char consumption is described with a shrinking core model. Turbulent combustion in the gas phase is modeled using a finite-rate/eddy-dissipation model. Radiation is considered by solving the radiative transport equation with the discrete ordinates model. Second-order upwind scheme is used to solve all gas phase equations. First, to validate the flow solver, we performed numerical modeling of a non-reacting particle-laden bluff-body flow. For the non-reacting flow, the predicted mean velocities of the gas phase and the particle phase are in good agreement with the experimental data. Next, we performed numerical modeling of the gasification process in the BYU gasifier. The predicted profiles of the mole fractions of the major species (i.e. CO, CO2, H2, and H2O) along the centerline are in reasonable agreement with the experimental data. The predicted carbon conversion at the gasifier exit agrees with the experimental data. The predicted temperature at the gasifier exit agrees with the estimated value based on water-gas shift equilibrium considerations. The numerical model was further applied to study the effects of the equivalence ratio, particle size, and swirl on the gasification process.

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Sa´nchez, Mauricio A., William H. Sutton et Carlos A. Sa´nchez. « Simulations of Thermal Performance for One- and Two-Dimensional Insulation and Aluminum Foil Fire Barriers ». Dans 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49265.

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Nonbearing walls made of concrete frequently include one or two-dimensional gaps between sections to allow the concrete exert expansion or contraction due to temperature transients. These section gaps require the use of a thermal fire barrier to stop a fire from spreading during a period of time. In some applications, such as seismic structures, fire barriers are large and form substructures and partial enclosures. These type of fire barriers are often manufactured by layering alternating blankets of ceramic fiber insulation with bounding thin metallic foil sheets. In this case, the barrier must meet the specifications and effectiveness given by the ASTM standard E-119. This effectiveness is determined by the requirement of maintaining structural integrity by allowing some heat release while not permitting the fire flame to pass through. Little data is available on the thermal interaction of 2-D corners and splicing the layers for large barriers. It is expected that spatial and angular effects might either degrade performance or even cause “hot spots” in a barrier wall. Therefore, a numerical simulation of the barrier is accomplished by utilizing the spectral/gray and directional/modeled data of each one of the components and by taking into account two common geometrical building shapes. This simulation analysis is done by coupling of the discrete ordinates method in radiation heat transfer and the energy equation to previously published thermophysical experimental data used as a validation of the properties for fire barrier materials. Some of the effects of directional and surface properties and radiative heat transfer in fire barrier materials have been included in the numerical model. The Fluent®-based numerical model is able to match thermal performance of previous test systems. Initial calculations suggest that a fire barrier consisting of a 2D corner geometry exposed to a fire from either side would be thermally less robust than a slab of the same characteristic aspect ratio. This approximation has shown a preferential orientation for the barrier to be positioned when a fire or other high energy source is postulated.

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Su, Ge, Zheng Tan et Jian Su. « Improved Lumped Models for a One-Dimensional Nonlinear Heat Conduction Problem ». Dans ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference collocated with the ASME 2007 InterPACK Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ht2007-32928.

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This work reports improved lumped-parameter models for a class of one-dimensional nonlinear heat conduction problems in a slab, cylinder or sphere with linearly temperature-dependent thermal conductivity and subject to combined convective and radiative boundary condition. The improved lumped models are obtained through two point Hermite approximations for integrals. It is shown by comparison with numerical solution of the original distributed parameter models that the higher order lumped models (H1, 1/H0, 0 approximation for slab and cylinder, H2, 1/H0, 0 for sphere) yield significant improvement of average temperature predictions over the classical lumped model.

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Foxe, M., C. Roecker, J. Boguski, I. Childres, G. Lopez, A. Patil, Y. P. Chen et I. Jovanovic. « Numerical model of graphene-based radiation detector response ». Dans 2010 IEEE Nuclear Science Symposium and Medical Imaging Conference (2010 NSS/MIC). IEEE, 2010. http://dx.doi.org/10.1109/nssmic.2010.5873843.

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Shmelev, D. L., S. A. Chaikovsky, I. V. Uimanov, A. G. Rousskikh et V. I. Oreshkin. « Numerical model of high current plasma source ». Dans 8th International Congress on Energy Fluxes and Radiation Effects. Crossref, 2022. http://dx.doi.org/10.56761/efre2022.s6-p-021102.

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In this paper, we numerically analyze a “capillary” type plasma source used to create plasma liners in gas puff z-pinch experiments. It is shown that erosion from a plasma source of this type, observed in the experiment, is provided by evaporation of the electrodes. Moreover, the main contribution comes from evaporation from the anode. The calculation results are in qualitative agreement with the experimental data.

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Zhang, Cheng, Kiel Schultheiss, Aniruddha Mitra et Mosfequr Rahman. « Parametric Studies of Coal Gasification in an Entrained-Flow Gasifier ». Dans ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51966.

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Although alternative energy sources, such as nuclear, wind, and solar, are showing great potential, hydrocarbon fuels are expected to continue to play an important role in the near future. There is an increasing interest in developing technologies to use hydrocarbon fuels cleanly and efficiently. The gasification technology that converts hydrocarbon fuels into syngas is one of these promising technologies. Entrained-flow gasifiers are the preferred gasifier design for future deployment due to their high carbon conversion, high efficiency and high syngas purity. Current designs of entrained-flow gasifiers still have serious problems such as injector failure, refractory failure, slag blockages, downstream fouling and poisoning, poor space efficiency, and lack of dynamic feedstock flexibility. To better understand the entrained-flow gasification process, we performed parametric studies of coal gasification in the laboratory-scale gasifier developed at Brigham Young University (BYU) using ANSYS FLUENT. An Eulerian approach was used to describe the gas phase, and a Lagrangian approach was used to describe the particle phase. The interactions between the gas phase and particle phase was modeled using the particle-source-in-cell approach. Turbulence was modeled using the standard k-ε model. Turbulent particle dispersion was taken into account by using the discrete random walk model. Devolatilization was modeled using a version of the chemical percolation devolatilization (CPD) model, and char consumption was described with a shrinking core model. Turbulent combustion in the gas phase was modeled using a finite-rate/eddy-dissipation model. Radiation was considered by solving the radiative transport equation with the discrete ordinates model. Second-order upwind scheme was used to solve all gas phase equations. First, the numerical model was validated by using experimental data for the mole fractions of the major species (CO, CO2, H2, and H2O) along the gasifier centerline. Then, the effects of concentrations of steam and oxygen at the inlets, and steam preheat temperature were studied. Model predictions found that increasing the steam concentration or steam preheat temperature in the secondary inlet generally decreases CO concentration, while increasing CO2 and H2 concentrations. Increasing the steam concentration in the secondary inlet showed no significant effects on predicted gas temperature in the gasifier. Increasing the oxygen concentration in the primary inlet generally increases gas temperature, CO and CO2 concentrations, while decreasing H2 concentration.

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Simons, N. R. S., A. A. Sebak et G. E. Bridges. « Input impedance model for DE-based numerical simulations of radiation problems ». Dans IEEE Antennas and Propagation Society International Symposium 1992 Digest. IEEE, 1992. http://dx.doi.org/10.1109/aps.1992.221803.

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Kuhlert, Karl, et Ulrich Renz. « A Comprehensive Radiation Model for Numerical Simulations of Pulverised Coal Flames ». Dans International Heat Transfer Conference 11. Connecticut : Begellhouse, 1998. http://dx.doi.org/10.1615/ihtc11.4290.

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Cai, Wenxiang, Jianxing Zhao, Xiaosong Wu et Bo Sun. « Influence of Radiation Model on Numerical Prediction of Two-Phase Reaction Flow ». Dans 2009 International Conference on Computational Intelligence and Software Engineering. IEEE, 2009. http://dx.doi.org/10.1109/cise.2009.5366244.

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Rapports d'organisations sur le sujet "Numerical slar radiation model"

LeGrand, Sandra, Christopher Polashenski, Theodore Letcher, Glenn Creighton, Steven Peckham et Jeffrey Cetola. The AFWA dust emission scheme for the GOCART aerosol model in WRF-Chem v3.8.1. Engineer Research and Development Center (U.S.), août 2021. http://dx.doi.org/10.21079/11681/41560.

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Airborne particles of mineral dust play a key role in Earth’s climate system and affect human activities around the globe. The numerical weather modeling community has undertaken considerable efforts to accurately forecast these dust emissions. Here, for the first time in the literature, we thoroughly describe and document the Air Force Weather Agency (AFWA) dust emission scheme for the Georgia Institute of Technology–Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) aerosol model within the Weather Research and Forecasting model with chemistry (WRF-Chem) and compare it to the other dust emission schemes available in WRF-Chem. The AFWA dust emission scheme addresses some shortcomings experienced by the earlier GOCART-WRF scheme. Improved model physics are designed to better handle emission of fine dust particles by representing saltation bombardment. WRF-Chem model performance with the AFWA scheme is evaluated against observations of dust emission in southwest Asia and compared to emissions predicted by the other schemes built into the WRF-Chem GOCART model. Results highlight the relative strengths of the available schemes, indicate the reasons for disagreement, and demonstrate the need for improved soil source data.

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