Готові списки джерел за темами / Simulation particulaire

Добірка наукової літератури з теми "Simulation particulaire"

Автор: Grafiati
Опубліковано: 8 червня 2024

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  1. Статті в журналах
  2. Дисертації
  3. Книги
  4. Частини книг
  5. Тези доповідей конференцій
  6. Звіти організацій

Статті в журналах з теми "Simulation particulaire":

1

Rivoalen, Elie, Serge Huberson, and Frédéric Hauville. "Simulation numérique des équations de Navier-Stokes 3D par une méthode particulaire." Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy 324, no. 9 (May 1997): 543–49. http://dx.doi.org/10.1016/s1251-8069(97)83187-9.

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2

Villedieu, Philippe, and Jouke Hylkema. "Une méthode particulaire aléatoire reposant sur une équation cinétique pour la simulation numérique des sprays denses de gouttelettes liquides." Comptes Rendus de l'Académie des Sciences - Series I - Mathematics 325, no. 3 (August 1997): 323–28. http://dx.doi.org/10.1016/s0764-4442(97)83964-x.

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3

VĂDUVA, Ion, and Mihăiţă DRĂGAN. "ON THE SIMULATION OF SOME PARTICULAR DISCRETE DISTRIBUTIONS." Review of the Air Force Academy 16, no. 2 (October 31, 2018): 17–30. http://dx.doi.org/10.19062/1842-9238.2018.16.2.2.

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4

Yang Fu, 杨馥, 陈文豪 Chen Wenhao, 陆彦宇 Lu Yanyu та 贺岩 He Yan. "高光谱分辨率的海洋碳颗粒剖面探测系统仿真". Infrared and Laser Engineering 52, № 5 (2023): 20220715. http://dx.doi.org/10.3788/irla20220715.

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5

Maierhofer, Paul, Marco Carminati, Giorgio Ferrari, Georg Röhrer, Marco Sampietro, and Alexander Bergmann. "Characterization of a Capacitive Sensor for Particulate Matter." Proceedings 2, no. 13 (December 17, 2018): 995. http://dx.doi.org/10.3390/proceedings2130995.

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We characterize a novel micro-sensor with pairs of interdigitated combs of microelectrodes designed to detect particles in air. We evaluate the sensor’s response to 1 µm Polystyrene Latex (PSL) particles experimentally and crosscheck the results with simulations. Experiment and simulation show good consistency. Based on the promising results we propose a redesign of the capacitive particle sensor with respect to PM2.5.
6

葉沛廷, 葉沛廷, та 蘇瑛敏 Pei-Ting Yeh. "基於透空式建築型態的街谷細懸浮微粒汙染物擴散數值模擬". 建築學報 117, № 117 (вересень 2021): 069–95. http://dx.doi.org/10.53106/101632122021090117004.

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<p>受發展影響都市空間結構呈現高層且高密度趨勢，頻繁的人為活動加上在密集空間裡持續排放汙染物，破壞都市微氣候環境造成負面效應(任超，2016；歐陽嶠暉，2005)，為改善惡化的都市環境，主要透過規劃與設計針對建物與街道空間型態進行優化，其中高密度的建築群影響周邊風環境，不利於街谷內汙染物的擴散，而透過透空式建築設計能減少建築迎風面面積，增加風通透性以改善都市環境 (香港屋宇署，2013)，過往研究多透過觀測的方式分析汙染物與氣象條件的關係，近期則針對汙染物進行電腦數值模擬，但採用顆粒物的模擬相對較少，因此本研究配合Hang, J. & Li, Y. G.(2010)理想城市10&times;9配置，設定透空式建築量體為長(30m)、寬(30m)、高(80m)，並以無透空建築為對照組，加上不同建築洞口高度(0.45h、0.65h及0.45-0.65h)為變項設計共4組研究方案，使用ANSYS Fluent v18進行風環境與PM2.5細懸浮微粒汙染物模擬。研究結果顯示:高層建築量體增加街道封閉性，導致空氣流通與汙染物擴散的阻礙，透空式建築能提高街道的滲透性改善空氣流通。隨著 Z 軸高度增加汙染物分佈受街谷空間及汙染源距離影響，因此較低的洞口具有較佳汙染物去除效果。連續且過長的街道讓汙染物累積於都市末端，建議維持足夠的都市空間讓街區空氣流通，以得到理想改善效果。</p> <p>&nbsp;</p><p>This study is based on opening buildings of length (30m), width (30m), and height (80m) combined with Hang, J. & Li, Y. G.(2010) ideal city 10 &times; 9 configurations, and building without hole is control group, different building opening heights (0.45h, 0.65h, and 0.45-0.65h) are designed as various groups of 4 research scenario. Using ANSYS Fluent v18 to simulate the wind environment and PM2.5 fine particulate matter. The results of the study found that the volume of high-rise buildings increased the sealing of the streets, leading to the obstruction of air circulation and the spread of pollutants. The opening buildings can increase the permeability of the streets and improve the air circulation. As the height of the Z-axis increases, the distribution of pollutants is affected by the space of the street canyon and the distance of the pollution source, so the lower hole has a better effect of removing pollutants. Continuous and long streets allow pollutants to accumulate at the end of the city. It is recommended to maintain sufficient urban space to allow air circulation in the blocks to obtain the desired improvement effect. </p> <p>&nbsp;</p>
7

Trunk, Robin, Timo Weckerle, Nicolas Hafen, Gudrun Thäter, Hermann Nirschl, and Mathias J. Krause. "Revisiting the Homogenized Lattice Boltzmann Method with Applications on Particulate Flows." Computation 9, no. 2 (January 27, 2021): 11. http://dx.doi.org/10.3390/computation9020011.

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The simulation of surface resolved particles is a valuable tool to gain more insights in the behaviour of particulate flows in engineering processes. In this work the homogenized lattice Boltzmann method as one approach for such direct numerical simulations is revisited and validated for different scenarios. Those include a 3D case of a settling sphere for various Reynolds numbers. On the basis of this dynamic case, different algorithms for the calculation of the momentum exchange between fluid and particle are evaluated along with different forcing schemes. The result is an updated version of the method, which is in good agreement with the benchmark values based on simulations and experiments. The method is then applied for the investigation of the tubular pinch effect discovered by Segré and Silberberg and the simulation of hindered settling. For the latter, the computational domain is equipped with periodic boundaries for both fluid and particles. The results are compared to the model by Richardson and Zaki and are found to be in good agreement. As no explicit contact treatment is applied, this leads to the assumption of sufficient momentum transfer between particles via the surrounding fluid. The implementations are based on the open-source C++ lattice Boltzmann library OpenLB.
8

Liu, Don, Yi Fan Wang, and Hai Bo Zhang. "Spectral Element Simulation of Complex Particulate Flows." Applied Mechanics and Materials 404 (September 2013): 318–23. http://dx.doi.org/10.4028/www.scientific.net/amm.404.318.

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This paper uses a mathematical model Virtual Identity Particles, developed by the author, to simulate conjugated motion of complex particles in a fluid. Assimilated the advantages of Eulerian and Lagrangian approaches, this model treats each particle as a variable source term to the fluid and is designed for simulating numerous particles in two-phase flows. The economic formulation in this model is the salient feature. Considering both precision and computational cost, this model maintains an excellent balance between accuracy and efficiency in modeling particulate flows with complex particles. Simulation results demonstrate that this model is viable for investigating complex particulate flows, especially at a moderately high particle number density.
9

Wang, Y. H., and S. C. Leung. "A particulate-scale investigation of cemented sand behavior." Canadian Geotechnical Journal 45, no. 1 (January 2008): 29–44. http://dx.doi.org/10.1139/t07-070.

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In this paper, triaxial tests and numerical simulations using the discrete element method (DEM) are combined to explore the underlying mechanisms of the unique behavior of artificially cemented sands. The experimental results show that strength enhancement, volumetric dilation, and the shear banding associated failure mode are observed in Portland cement sand; these features become more pronounced with increasing cement content. Different responses are found in gypsum-cemented sand even though both types of cemented sand specimens were prepared under very similar void ratios before shearing. The DEM simulations on the Portland cement sand were carried out under two particular arrangements (i.e., the use of small cementing particles and flexible membrane boundaries). The simulation results reveal that particles in the bonding network jointly share the loading and many micro force-chains associated with cementation are created. Compared with uncemented sand, a more stable and stronger force–chain complex subjected to smaller force concentration is formed in cemented sand, which gives rise to higher strength. Intensive bond breakage, concentrated relative particle movement, column-like force chains, great particle rotation, and high local porosity are found inside the shear band. The bonded clusters remain at large strains to help stabilize the particle arch and therefore to maintain the volumetric dilation.
10

Song, Xin-Yi, Qing-Chang Lu, and Zhong-Ren Peng. "Spatial Distribution of Fine Particulate Matter in Underground Passageways." International Journal of Environmental Research and Public Health 15, no. 8 (July 25, 2018): 1574. http://dx.doi.org/10.3390/ijerph15081574.

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The unfavorable locations of underground infrastructures and poor ventilation facilities can result in the deterioration of enclosed air quality. Some researchers have studied air quality and ventilation measures in different types of underground buildings. However, few studies have investigated the pollution in pedestrian passageways connecting underground structures. Hence, in this paper, we attempted to investigate the spatial distribution of fine particulate matter (PM2.5) in underground passageways. First, measurements were designed and conducted in a pedestrian passageway beneath the Shanghai South Railway Station, Shanghai, China. Second, numerical simulations were performed based on computational fluid dynamic (CFD) technology. Finally, the numerical simulations were extended to examine impacts of the ventilation measures on PM2.5 concentration with different inlet positions and air velocity in underground passageways. The simulation results showed good agreement with the experimental data, and the numerical model was validated to be an effective method to investigate the spatial distribution of PM2.5 in underground passageways. Results suggest that building additional entrances is an advisable method for improving air quality in the underground passageways of the Shanghai South Railway Station, while jet fans are not recommended. Findings of this study offer suggestions for mitigating PM2.5 pollution in underground passageways.
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Дисертації з теми "Simulation particulaire":

1

Minea, Tiberiu. "Simulation particulaire d'une decharge magnetron radio-frequence. Comparaison a l'experience." Paris 11, 1998. http://www.theses.fr/1998PA112400.

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Cette these est dediee a l'etude d'une decharge magnetron radiofrequence (rf) etant motivee par le besoin de comprehension des mecanismes de maintien d'une telle decharge. Nous avons tente un rapprochement entre les decharges magnetrons et les propulseurs ioniques, tous deux magnetises et ayant des proprietes similaires, notamment pour la pulverisation de materiau. Un magnetron plan rf a ete utilise comme dispositif d'erosion et il a ete caracterise par des diagnostics electriques, par spectroscopie et par profilometrie. Pour cela nous avons utilise differents gaz rares pour des cibles metalliques ou dielectriques. En parallele, une simulation particulaire a ete developpee pour decrire la repartition spatiale (deux dimensions - 2d) et temporelle (rf) des principaux parametres d'un plasma magnetron. Outre la spectroscopie, nous avons utilise un code monte carlo de type trim pour l'etude de la pulverisation de ceramiques. Les resultats portent sur le depot de puissance dans le plasma magnetron rf, sur les mecanismes d'entretien de cette decharge et sur la caracterisation spatiale des flux en energie des ions responsables de la pulverisation des cibles. La connaissance des tensions sur la cible nous a permis un choix realiste de conditions de frontiere dans la simulation particulaire, mais aussi la comparaison entre les predictions du modele et l'experience. L'interpretation des resultats numeriques a mis en evidence une double contribution au chauffage des electrons dans la decharge, due aux processus stochastiques en volume engendres par les oscillations de la gaine cathodique () et due a l'emission secondaire (). Un bon accord a ete trouve entre les resultats du calcul et ceux de l'experience concernant le profil d'erosion dans le cas d'une cathode metallique. L'etude par spectroscopie optique d'emission a mis en evidence la pulverisation de ceramiques dans notre magnetron et dans le propulseur a plasma.
2

Zouari, Bassem. "Modélisation et simulation de l'enlèvement de revêtements polymériques par impact particulaire." Paris, ENSAM, 2001. http://www.theses.fr/2001ENAM0010.

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Le décapage des revêtements polymériques par impacts de particules abrasives est un nouveau procédé qui vient remplacer les procédés chimiques polluants. Notre travail porte sur la compréhension des phénomènes physiques intervenant dans l'enlèvement des revêtements par impacts. Dans un premier temps, nous avons élaboré un dispositif expérimental pour étudier des mono-impacts avec des particules sphériques sur des cibles en alliages d'aluminium (A2024) revêtues par une peinture en polyuréthane de nuance (PAC 33). A travers ces essais, nous avons montré que le délaminage de la peinture est le mécanisme essentiel de l'enlèvement de matière. Dans un second temps, nous avons identifé un modèle rhéologique du comportement de la peinture dans les conditions réelles de sollicitation à savoir des grandes vitesses de déformation et des grandes déformations. Nous avons utilisé les techniques inverses pour trouver les coefficients de la loi d'écoulement de Johnson-Cook à partir des dimensions des empreintes d'imapct. Pour comprendre les origines de ce délaminage nous avons simulé dans une troisième étape les essais d'impact à l'aide d'un programme éléments finis de dynamique explicite (LS-DYNA). Nous avons remarqué que l'enlèvement de la peinture est le résultat des trois phénomènes suivants : - initiation du délaminage dès les premiers instatns d'impact suite aux contraintes de cisaillement très élevées à l'interface ; - flambement de la peinture suite aux fortes contraintes radiales de compression dans le film provoquées par la pénétration de la particule dans le revêtement ; - propagation de la zone délaminée suivant le mode I de rupture.
3

Euzenat, Charly. "Contributions à la simulation de l’enlèvement de matière par abrasion." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST059.

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La réalisation des pièces mécaniques à forte valeur ajoutée implique des temps d'usinage conséquents et nécessite parfois une finition des surfaces fonctionnelles par abrasion pour atteindre les spécifications requises. La bonne définition des paramètres de la gamme de fabrication joue un rôle important dans l'obtention l'état de surface final sur les pièces produites. Dans ce contexte, la maîtrise des exigences est encore réalisée de manière empirique.La thèse sur le polissage des surfaces fonctionnelles et plus particulièrement sur la prédiction et la simulation réaliste des effets des procédés d'abrasion sur la topographie des surfaces. Les travaux proposés contribuent à étudier de nouvelles méthodes de simulation pour l'abrasion. Plus particulièrement, l'enjeu scientifique de ces travaux est de créer une rupture vis-à-vis des simulations classiques à base de maillages, par l'utilisation de méthodes particulaires, et d'en évaluer les performances dans ce contexte. Les résultats de simulation obtenus dans le cadre d'essais d'indentation et de rayage ont été comparés à des essais et sont concluants. Cependant, les temps de simulation sont trop grands pour envisager une simulation d'abrasion complète mettant en œuvre le passage de centaines de grains abrasifs.Pour pallier ces difficultés, le développement d'un modèle d'abrasion basé sur la représentation implicite des surfaces a été mené. Le procédé d'abrasion est modélisé en utilisant ce formalisme de représentation des surfaces. Une gamme de fabrication complète allant de l'usinage à l'abrasion est simulée avec succès et est validée expérimentalement. Les modèles étudiés pourraient être une base au développement d'un outil de simulation industriel. L'apport des simulations au profit de l'automatisation des opérations d'abrasion et de l'optimisation des gammes de fabrication pourrait permettre d'augmenter la productivité et la qualité des pièces mécaniques
The production of mechanical parts with high added value involves significant machining times and sometimes requires the functional surfaces to be finished by abrasion in order to achieve the required specifications. The correct definition of the parameters of the manufacturing process plays an important role in obtaining the final surface finish on the parts produced. In this context, the control of involved parameters is still carried out empirically.The thesis focuses on the polishing of functional surfaces and in particular on the prediction and realistic simulation of the effects of abrasion processes on surface topography. The proposed work contributes to the study of new simulation methods for abrasion. More specifically, the scientific challenge of this work is to create a breakthrough with conventional simulations, using meshless methods, and to evaluate their performance in this context. The simulation results obtained in indentation and scratching tests have been compared to experimental results and are in agreement. However, the simulation times are too long to envisage a complete abrasion simulation involving the passage of hundreds of abrasive grains.To overcome these difficulties, the development of an abrasion model based on the implicit representation of surfaces was carried out. The abrasion process is modelled using this surface representation formalism. A complete manufacturing process from machining to abrasion is successfully simulated and experimentally validated. The models studied could be a possible foundation for the development of an industrial simulation framework. The contribution of simulations to the automation of abrasion operations and the optimization of manufacturing processes could help to increase the productivity and quality of mechanical parts
4

Zhang, Qijie. "Simulation de la matière particulaire dans la région parisienne, en particulier de l'aérosol organique." Paris 7, 2012. http://www.theses.fr/2012PA077206.

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Les activités humaines dans les grandes agglomérations ("mégalopoles") provoquent des émissions de polluants importantes, avec des effets négatifs sur la qualité de l'air et la santé humaine à l'échelle locale et régionale. Les particules fines (PM) sont l'une des plus grandes préoccupations pour la santé. Les aérosols organiques constituent une partie importante de paricules fines, mais il y a encore de grandes lacunes dans les connaissances sur leurs voies de formation et il y a une incertitude considérable dans leur modélisation 3D. Dans cette thèse, les simulations de PM₂. ₅ avec le modèle de chimie-transport régionaux CHIMERE ont d'abord été évaluées avec les mesures recueillies à Paris au printemps 2007. Les résultats du modèle montrent une bonne performance de simuler l'apparition de pics, surtout pour les aérosols inorganiques qui proviennent principalement de transport à longue distance de l'Europe Nord-Est et Centrale. L'aérosol organique primaire (POA) simulé est surestimé quand il est considéré comme non-volatile par un facteur de deux, tandis que l'aérosol organique secondaire (SOA) est sous-estimé par un facteur de plus de 2. Afin d'améliorer la performance du modèle de simulation de l'aérosol organique, l'approche "Volatility Basis Set" qui formalise les nouvelles connaissances sur la volatilité de POA et le vieillissement chimique de SOA sont mises en oeuvre dans CHIMERE. Les simulations du modèle sont évaluées avec les observations au sol et aéroportées obtenues lors des deux campagnes de terrain intensives effectuées dans l'agglomération parisienne en été 2009 et hiver 2009/2010 dans le cadre du projet européen MEGAPOLI. La simulation de l'aérosol organique est significativement améliorée lorsque l'on tient compte de la volatilité des POA et l'oxydation multi-étapes de COV semi volatil lors de la campagne d'été. L'advection des masses d'air continentales à l'agglomération parisienne avec des niveaux de fond de SOA soit d'origine anthropique ou biogénique, est bien restituée par le modèle. L'accumulation de SOA dans le panache est surestimée par un facteur de deux, quand normalisée à la production photochimique d'ozone, ce facteur est dans l'incertitude de l'approche VBS. Pendant la campagne d'hiver, la formation de la SOA reste sous-estimée. Ces résultats représentent clairement des progrès dans la modélisation de l'aérosol organique dans et autour d'une grande agglomération urbaine. Le modèle a été utilisé pour estimer les contributions des sources de l'aérosol organique dans l'agglomération et dans le panache en été 2009. Dans l'agglomération, l'advection de SOA biogéniques, anthropiques et du fond de l'extérieur a été dominante, tandis que le POA émis localement à environ un quart de l'aérosol organique au total. Dans le panache, la formation de SOA anthropique, et aussi de POA âgés devient dominante. Ces résultats sont en accord général avec les études de l'attribution des sources à partir d'observations
Human activities in large agglomerations ("megacities") cause large pollutant emissions, with negative effects on air quality and human health at a local and regional level. Fine particulate matter (PM) is one of the greatest concerns for health. Organic aerosol makes up a large part of fine PM, but there are still large gaps in the knowledge on its formation pathways and there is considerable uncertainty in its 3D modeling. In this thesis, PM₂. ₅ simulations with the regional chemistry-transport model CHIMERE were first evaluated with measurement date collected in Paris in springtime, 2007. The model results show good performance of simulating occurrence of peaks, especially for inorganic aerosols which mainly originate from long range transport from Northeastern and Central Europe. Modeled primary organic aerosol (POA) is overestimated when considered as non-volatile by a factor of two, while secondary organic aerosol (SOA) is underestimated by a factor of more than two. In order to improve the model performance of organic aerosol simulation, the volatility basis set approach which formalizes new knowledge on POA volatility and on SOA chemical aging is implemented into CHIMERE. Model simulations are evaluated with ground based and airborne observations obtained during two intensive field campaigns performed in the Paris agglomeration in summer 2009 and winter 2009/2010 in the frame of the European MEGAPOLI project. The simulation for organic aerosol is improved when taking into account POA volatility and multistep oxidation of semivolatile VOC during the summer campaign. Advection of continental air masses to the Paris agglomeration with enhanced SOA levels either from anthropogenic or biogenic origin, is well restituted by the model. SOA build-up in the plume is overestimated by a factor of two when normalized to photochemical ozone production, but this factor is within the uncertainty of the VBS approach. During the winter campaign, SOA formation is still underestimated. These results clearly represent progress in the modeling of organic aerosol in and around a large urban agglomeration. The model was used to estimate sources contributing for summer 2009 to organic aerosol in the agglomeration and in the plume. Within the agglomeration, advection of biogenic, anthropogenic and background SOA from outside was dominant, while locally emitted POA accounts to about a quarter of total OA. In the plume, anthropogenic SOA formation, and to some extent also SOA formation from aged POA becomes dominant. These results are in broad agreement with source apportionment studies from observations
5

Ben, Salem Farah. "Réception particulaire pour canaux multi-trajets évanescents en communications radiomobiles." Toulouse 3, 2002. http://www.theses.fr/2002TOU30142.

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6

Jiang, Yuchao. "Quelques problèmes de physique et simulation particulaire de plasmas froids partiellement magnétisés et de sources d'ions." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30057.

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Dans cette thèse, nous illustrons certains des enjeux de la physique et de la modélisation des plasmas partiellement magnétisés avec trois exemples spécifiques qui correspondent aux études en cours au sein du groupe GREPHE du laboratoire LAPLACE: 1) Extraction d'électrons dans les sources d'ions négatifs pour l'injection de faisceaux neutres en fusion 2) Instabilités dans les décharges magnétron et propulseurs à courant de Hall 3) Confinement de plasma par festons magnétiques ("magnetic cusps") - Dans l'étude des sources d'ions négatifs pour la fusion, le groupe GREPHE a pour objectif de mieux comprendre la physique de la source d'ions négatifs, et plus spécifiquement, les questions du transport du plasma à travers le filtre magnétique et de l'extraction des ions négatifs du plasma. L'un des problèmes importants de ces sources d'ions négatifs est de minimiser le courant d'électrons qui sont co-extraits avec les ions négatifs. Dans cette thèse, nous nous concentrons sur cet aspect et nous essayons de comprendre et de quantifier comment les électrons peuvent être extraits à travers une ouverture de grille quand un "cusp" magnétique est placé devant l'ouverture. Nous discutons, à l'aide de simulations 3D PIC MCC (Particle-In-Cell Monte Carlo Collisions), les contributions des différentes dérives électroniques (dérive ExB, dérive Grad B et dérive de courbure) et des instabilités à l'extraction d'électrons à travers une ouverture de la grille. - Les propulseurs à courant de Hall et les décharges magnétron sont des dispositifs cylindriques à champs croisés (ExB, champ magnétique B radial et champ électrique E axial). On sait depuis longtemps que des instabilités sont présentes dans ces décharges, conduisant à un transport d'électrons anormal important. Dans cette thèse, nous nous concentrons sur un type particulier d'instabilité (non-uniformité en rotation, ou "rotating spoke"), qui est présent dans les propulseurs à courant de Hall et les décharges de magnétron et qui apparaît dans les expériences comme une non-uniformité lumineuse se déplaçant dans la direction azimutale. Dans ce travail, nous utilisons une simulation 2D PIC MCC pour effectuer une étude paramétrique de cette instabilité. Nous montrons que, dans certaines conditions où ces non-uniformités ont été observées dans les expériences, la dérive des électrons Grad B joue un rôle majeur dans le chauffage des électrons et dans la formation et l'entretien de ces "rotating spokes". [...]
In this thesis we will illustrate some of the issues in the physics and modeling of partially magnetized plasmas with three specific examples that correspond to ongoing studies in the GREPHE group of the LAPLACE laboratory: 1) Electron extraction in negative ion sources for neutral beam injection in fusion 2) Instabilities in magnetron discharges and Hall thrusters 3) Plasma confinement by magnetic cusps - In the study of negative ion sources for fusion, the aim of the GREPHE group is to better understand the physics of the negative ion source, and more specifically, the questions of plasma transport across the magnetic filter and of negative ion extraction from the plasma. One of the important issues in these negative ion sources is to minimize the current of electrons that are co-extracted with the negative ions. In this thesis we focus on this aspect and we try to understand and quantify how electrons can be extracted through a grid aperture when a magnetic cusp is placed in front of the aperture. We discuss, with the help of 3D PIC MCC (Particle-In-Cell Monte Carlo Collisions) simulations, the contributions of different electron drifts (ExB drift, Grad B drift and curvature drift) and instabilities to electron extraction through a grid aperture.- Hall thrusters and magnetron discharges are ExB cylindrical devices with radial magnetic field and axial electric field. It has been known for a long time that instabilities are present in these discharges, leading to important anomalous electron transport. In this thesis we focus on one particular type of instability, called "rotating Spoke", which is known to be present in Hall thrusters and magnetron discharges and is apparent in the experiments as a luminous non-uniformity rotating in the azimuthal direction. In this work we use a 2D PIC MCC simulation to perform a parametric study of this instability. We show that, in some conditions where rotating spokes have been observed in the experiments, Grad B electron drift plays a major role in electron heating and in the formation and maintenance of the rotating spokes.- Magnetic cusps have been used for more than 60 years to confine the plasma in a large variety of conditions. An important parameter characterizing plasma confinement by cusps is the effective loss area in the presence of magnetic cusps. Some semi-empirical theories have been proposed to quantify the effective loss area and their predictions have been compared with numerous experimental results. In spite of these efforts there is no fully reliable expression of the effective wall loss as a function of different parameters such as magnetic field, electron temperature, ion mass, gas pressure, etc... We describe in this thesis an attempt at obtaining scaling laws for the effective loss width of magnetic cusps, based on 2D PIC MCC simulations
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LU, HUI ZHONG. "Simulation des ecoulements externes visqueux incompressibles par une methode de couplage : methode des differences finies/methode particulaire." Paris 11, 1996. http://www.theses.fr/1996PA112156.

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Ce travail presente une technique de decomposition de domaine avec recouvrement pour la simulation des ecoulements externes visqueux incompressibles a grand nombre de reynolds. Dans les sous domaines proches des parois, on utilise une approximation par differences finies pour bien representer le caractere parabolique des equations de navier-stokes dans les couches limites. Dans le sous domaine loin des parois, on utilise une approximation particulaire afin d'obtenir une approximation consistante de la condition a l'infini et minimiser la diffusion numerique tout en conservant une bonne stabilite sur la derivee convective. On introduit d'abord en dimension 2 des methodes des differences finies et une methode particulaire deterministe convenable pour le couplage. Ensuite, on presente deux techniques de couplage en dimension 2: l'une utilise la methode de differences finies comme correction de la methode particulaire dans les couches limites ; l'autre consiste a adopter directement la methode de schwarz. Apres, on valide notre methode en comparant nos resultats numeriques soit avec une approximation monodomaine obtenue par differences finies soit avec des resultats experimentaux. La methode de couplage est aussi utilisee pour simuler les ecoulements autour de plusieurs obstacles (eventuellement en mouvement relatif). A la fin, la technique est etendue en dimension 3 et utilisee pour simuler l'ecoulement autour d'une plaque plane carree
8

Guyot-Delaurens, Frédérique. "Application de la méthode particulaire déterministe à la simulation du modèle cinétique de dispositifs électroniques inhomogène unidimensionnels." Palaiseau, Ecole polytechnique, 1990. http://www.theses.fr/1990EPXX0001.

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On s'intéresse à la simulation de Boltzmann des semiconducteurs, par une méthode particulaire à poids variables. Dans cette méthode, les particules se déplacent suivant une dynamique non collisionnelle, tandis que les collisions sont traitées de manière déterministe, par la variation des poids des particules. Dans la première partie, on suppose le champ électrique homogène, et on applique la méthode a un opérateur de collisions non linéaire (correspondant à un semi-conducteur fortement dope), puis à un système couple d'équations de Boltzmann ; ce système est issu de la modélisation du transport électronique et des effets quantiques à l'interface d'une hétérojonction. Dans la deuxième partie, on tient compte du champ électrique créé par le déplacement des charges, en résolvant un système couple Boltzmann-Poisson. On compare, sur un problème simplifie, plusieurs méthodes pour coupler numériquement le déplacement des particules et le calcul du champ. On applique ensuite ces méthodes a la simulation de structures électroniques inhomogènes, unidimensionnelles.
9

Ikardouchene, Syphax. "Analyses expérimentale et numérique de l'interaction departicules avec un jet d'air plan impactant une surface.Application au confinement particulaire." Thesis, Paris Est, 2019. http://www.theses.fr/2019PESC1046.

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La thèse vise à qualifier les performances de confinement de rideaux d’air vis-à-vis de pollution particulaire. Plus précisément, elle vise à mettre en place, caractériser et améliorer des barrières de confinement particulaire par des jets d'air plans placés en périphérie de machines tournantes abrasives utilisées pour décaper les surfaces amiantées
The thesis aims to qualify the containment barriers for particles. Specifically, it aims to develop, characterize and improve particulate confinement barriers by jets of air placed at the periphery of abrasive rotating machines used to scour the surfaces containing asbestos
10

Douillet-Grellier, Thomas. "Etude comparative des méthodes d'origine particulaire SPH et LBM pour la simulation d'écoulements polyphasiques intermittents dans des conduites." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLN030/document.

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L’objectif de cette thèse est d’étudier les apports et les limitations de deux méthodes d’origine particulaire, SPH et LBM, dans le cadre de la simulation des écoulements à bouchons dans des conduites. Dans l’industrie pétrolière, ce type d’écoulement, que l’on retrouve par exemple dans les pipelines qui acheminent le pétrole et le gaz jusqu’aux raffineries, est connu pour endommager les installations et pour réduire l’efficacité du transport des fluides. Il est donc important de bien comprendre leur formation. Nous avons donc implémenté ces deux méthodes, ainsi que leurs variantes polyphasiques, et avons mené une campagne de validation et de comparaison afin de sélectionner la méthode la plus adéquate, pour poursuivre ensuite avec des simulations de cas plus appliqués et réalistes. Les contributions présentées se concentrent principalement sur trois axes. Tout d’abord, il a fallu construire les codes de calcul nécéssaires, les valider puis comparer des différentes formulations polyphasiques disponibles pour SPH et LBM. Ensuite, nous avons développé des conditions aux limites d’entrée/sortie adaptées au contexte polyphasique pour être en mesure d’injecter les fluides avec des vitesses imposées et de ler évacuer du domaine avec un pression donnée. Enfin, nous avons simulé différents cas d’écoulements à bouchons académiques avec SPH et LBM, puis sur des cas appliqués avec des géométries réalistes et des ratios de densité et de viscosité de type air/eau avec SPH seulement
The main objective of this thesis is to study the contributions and limitations of two particle- based methods, SPH and LBM, for the simulation of slug flows in pipes. In the petroleum industry, these flow regimes, found for example during the transportation of oil and gas from reservoirs to refinery facilities through pipelines, are highly undesirable because they are known to damage facilities and to reduce flow efficiency. Therefore, it is important to understand its formation. We have implemented both methods, as well as their multiphase variants, and have led a validation and comparison campaign in order to to select the most suited method and to continue with simulations of more applied and realistic cases. The main contributions of this work can summarized in 3 points. First, we had to write the necessary computation codes, validate them and compare the different multiphase formulations available for SPH and LBM. Then, we have developed inlet/outlet boundary conditions adapted to the multiphase context so that we are able to inject fluids with prescribed velocities and let them exit he domain with a given pressure. Finally, we have simulated different academic test cases of slug flows with SPH and LBM and then on applied cases with realistic geometries and air-water like density and viscosity ratios with SPH only
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Книги з теми "Simulation particulaire":

1

Zohdi, Tarek I. An introduction to modeling and simulation of particulate flows. Philadelphia, PA: Society for Industrial and Applied Mathematics, 2007.

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2

Randall, Clive William. The application of contact mechanics to the numerical simulation of particulate material. Birmingham: Aston University. Department of Civil Engineering, 1989.

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3

Davidson, Moreira, and Vilhena Marco, eds. Air pollution and turbulence: Modeling and applications. Boca Raton: Taylor & Francis, 2010.

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4

Flanagan, Thomas Bernard. Signal controlled roundabouts: An investigation into the efficiency of signal controlled roundabouts utilizing simulation techniques with particular reference to junctions with three approaches. Bradford, England: University of Bradford, 1987.

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5

Office, General Accounting. Air pollution: EPA's actions to resolve concerns with the fine particulate monitoring program : report to the Chairman, Subcommittee on VA, HUD, and Independent Agencies, Committee on Appropriations, House of Representatives. [Washington, D.C.]: The Office, 1999.

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6

Lenhard, Johannes. Computer Simulation. Edited by Paul Humphreys. Oxford University Press, 2015. http://dx.doi.org/10.1093/oxfordhb/9780199368815.013.42.

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This article interprets computer simulation modeling as a new type of mathematical modeling that comprises a number of interdependent components, among them experimentation, visualization, and adaptability. Furthermore, it is argued, simulation modeling can be characterized as a particular style of reasoning, namely a combinatorial style, that assembles and balances elements from different other styles. Two examples are discussed that exemplify the transformative force of this style: what counts as “understanding phenomena” and what counts as a “solution.” Both are seminal pieces of traditional mathematical modeling and both are transformed, if not inverted, in simulation modeling. Finally, some challenges are considered that computer simulations pose for philosophy of science.
7

Allen, Michael P., and Dominic J. Tildesley. Some tricks of the trade. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198803195.003.0005.

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This chapter concentrates on practical tips and tricks for improving the efficiency of computer simulation programs. This includes the effect of using truncated and shifted potentials, and the use of table look-up and neural networks for calculating potentials. Approaches for speeding up simulations, such as the Verlet neighbour list, linked-lists and multiple timestep methods are described. The chapter then proceeds to discuss the general structure of common simulation programs; in particular the choice of the starting configuration and the initial velocities of the particles. The chapter also contains details of the overall approach to organising runs, storing the data, and checking that the program is working correctly.
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Birks, Daniel. Computer Simulations. Edited by Gerben J. N. Bruinsma and Shane D. Johnson. Oxford University Press, 2018. http://dx.doi.org/10.1093/oxfordhb/9780190279707.013.36.

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In recent years, the field of social simulation has been dominated by the individual, or agent-based, computational model (ABM). ABMs provide unique means to explore complex social systems by allowing researchers to construct explicit models of the individual actors and interactions that make them up - people, peer groups, companies, nations, trade, reproduction, victimization, and so on, This chapter aims to provide the reader with a primer in the social simulation method and in particular the application of ABM in the field of environmental criminology. It begins by discussing the rationale behind the ABM approach. Subsequently, drawing on two illustrative simulations, it summarizes fundamental processes involved in designing, constructing, verifying, calibrating, validating, and utilizing ABM. It concludes by discussing some of the overarching strengths and limitations of the approach, and by discussing several areas of research that might aid in furthering the use of ABM within the field of environmental criminology.
9

Zohdi, T. I. An Introduction to Modeling and Simulation of Particulate Flows (Computational Science and Engineering). SIAM, Society for Industrial and Applied Mathematics, 2007.

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10

Computational Fluid And Particle Dynamics In The Human Respiratory System. Springer, 2012.

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Частини книг з теми "Simulation particulaire":

1

Ueda, Kyohei, Yoshikazu Tanaka, Anurag Sahare, Ahmed Elgamal, Zhijian Qiu, Rui Wang, Tong Zhu, et al. "LEAP-ASIA-2019 Simulation Exercise: Comparison of the Type-B and Type-C Numerical Simulations with Centrifuge Test Results." In Model Tests and Numerical Simulations of Liquefaction and Lateral Spreading II, 61–99. Cham: Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-48821-4_3.

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AbstractThis chapter presents a summary of Type-B and Type-C numerical simulations submitted by nine numerical simulation teams that participated in the LEAP-ASIA-2019 prediction campaign, with the results of a selected set of centrifuge model tests on the seismic behavior of a uniform-density, 20-m-long, and 5-degree sandy slope. Time histories of response accelerations, excess pore water pressures, and lateral displacements at the ground surface are compared to the experimental results. A majority of Type-B and Type-C numerical simulations were capable of simulating well the experimental trends observed in the centrifuge tests; in particular, Type-C simulations were found to capture the measured responses more accurately by adjusting the model parameters. Although it is quite challenging to perfectly capture all measured responses (e.g., accelerations, pore pressures, and displacements), the simulation exercises demonstrate that the numerical simulations can be further improved by accumulating high-quality experimental results as a database.
2

Herrmann, H. J. "Simulating Moving Granular Media." In Mobile Particulate Systems, 281–304. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-015-8518-7_18.

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3

Walton, O. R. "Force Models for Particle-Dynamics Simulations of Granular Materials." In Mobile Particulate Systems, 367–80. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-015-8518-7_21.

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4

Knepley, Matthew G., Vivek Sarin, and Ahmed H. Sameh. "Parallel simulation of particulate flows." In Solving Irregularly Structured Problems in Parallel, 226–37. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/bfb0018542.

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5

Savage, S. B. "Marginal Ice Zone Dynamics Modelled by Computer Simulations Involving Floe Collisions." In Mobile Particulate Systems, 305–30. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-015-8518-7_19.

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6

Aktulga, H., V. Ravindra, A. Grama, and S. Pandit. "Machine Learning Techniques in Reactive Atomistic Simulations." In Lecture Notes in Energy, 15–52. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-16248-0_2.

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AbstractThis chapter describes recent advances in the use of machine learning techniques in reactive atomistic simulations. In particular, it provides an overview of techniques used in training force fields with closed form potentials, developing machine-learning-based potentials, use of machine learning in accelerating the simulation process, and analytics techniques for drawing insights from simulation results. The chapter covers basic machine learning techniques, training procedures and loss functions, issues of off-line and in-lined training, and associated numerical and algorithmic issues. The chapter highlights key outstanding challenges, promising approaches, and potential future developments. While the chapter relies on reactive atomistic simulations to motivate models and methods, these are more generally applicable to other modeling paradigms for reactive flows.
7

Helmig, Thorsten, Hui Liu, Simon Winter, Thomas Bergs, and Reinhold Kneer. "Development of a Tool Temperature Simulation During Side Milling." In Lecture Notes in Production Engineering, 308–17. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-34486-2_22.

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AbstractCurrent modeling approaches of cutting processes require on the one hand extensive numerical and analytical simulations and further an experienced user in the field of numerical simulations, which makes a large-scale application time-consuming to apply.Therefore, the goal is to implement existing models into an established side-milling simulation program aiming for a computationally fast and user-friendly simulation approach capable of predicting transient tool temperatures along the cutting edge. Aim of this work is the development of the thermal model, which can later be implemented into existing programs. The model process involves the following two major steps: First, a geometric engagement simulation of the milling process with a parameterizable tool geometry is performed. These results are used to form a database linking the specific cutting force components with the heat flux components. Second, a three-dimensional transient heat conduction model of the cutter is established, applying the calculated heat flux components as boundary conditions in the simulation. Finally, first results of the performed simulation are presented and evaluated, in particular to validate the work flow and user accessibility. Future studies will then focus on further parameter analysis and experimental validation.
8

Michaelides, Efstathios E. Stathis. "Numerical Modeling and Simulations." In Heat and Mass Transfer in Particulate Suspensions, 47–88. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4614-5854-8_2.

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9

Goddard, J. D., A. K. Didwania, and X. Zhuang. "Computer Simulations and Experiment on the Quasi-Static Mechanics and Transport Properties of Granular Materials." In Mobile Particulate Systems, 261–80. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-015-8518-7_17.

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10

Seakins, Paul, Arnaud Allanic, Adla Jammoul, Albelwahid Mellouki, Amalia Muñoz, Andrew R. Rickard, Jean-François Doussin, et al. "Analysis of Chamber Data." In A Practical Guide to Atmospheric Simulation Chambers, 241–91. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-22277-1_7.

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AbstractIn this chapter, we focus on aspects of analysis of typical simulation chamber experiments and recommend best practices in term of data analysis of simulation chamber results relevant for both gas phase and particulate phase atmospheric chemistry. The first two sections look at common gas-phase measurements of relative rates and product yields. The simple yield expressions are extended to account for product removal. In the next two sections, we examine aspects of particulate phase chemistry looking firstly at secondary organic aerosol (SOA) yields including correction for wall losses, and secondly at new particle formation using a variety of methods. Simulations of VOC oxidation processes are important components of chamber work and one wants to present methods that lead to fundamental chemistry and not to specific aspects of the chamber that the experiment was carried out in. We investigate how one can analyse the results of a simulation experiment on a well-characterized chemical system (ethene oxidation) to determine the chamber-specific corrections. Finally, we look at methods of analysing photocatalysis experiments, some with a particular focus on NOx reduction by TiO2-doped surfaces. In such systems, overall reactivity is controlled by both chemical processes and transport. Chambers can provide useful practical information, but care needs to be taken in extrapolating results to other conditions. The wider impact of surfaces on photosmog formation is also considered.

Тези доповідей конференцій з теми "Simulation particulaire":

1

CHERFILS, Jean-Marc, Louis BLONCE, Grégory PINON, and Elie RIVOALEN. "Simulation en méthode particulaire des sollicitations hydrodynamiques d'ouvrages marins." In Journées Nationales Génie Côtier - Génie Civil. Editions Paralia, 2010. http://dx.doi.org/10.5150/jngcgc.2010.009-c.

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2

CHERFILS, Jean-Marc, Grégory PINON, and Elie RIVOALEN. "Simulation en méthode particulaire d'un écoulement de houle sur des ouvrages marins." In Journées Nationales Génie Côtier - Génie Civil. Editions Paralia, 2012. http://dx.doi.org/10.5150/jngcgc.2012.003-c.

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3

Bedi, Tanya Kaur, and Shankha Pratim Bhattacharya. "Indoor air quality assessment based on particulate matter contamination." In 2023 Building Simulation Conference. IBPSA, 2023. http://dx.doi.org/10.26868/25222708.2023.1351.

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4

Konstandopoulos, Athanasios G., Margaritis Kostoglou, Nickolas Vlachos, and Evdoxia Kladopoulou. "Progress in Diesel Particulate Filter Simulation." In SAE 2005 World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2005. http://dx.doi.org/10.4271/2005-01-0946.

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5

Pagalthivarthi, Krishnan V., John M. Furlan, and Robert J. Visintainer. "Finite Element Prediction of Multi-Size Particulate Flow Through Three-Dimensional Pump Casing." In ASME/JSME/KSME 2015 Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/ajkfluids2015-31129.

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Flow through centrifugal pump casing is highly complex in nature due to the complex geometry of the casing. While simplified two dimensional modeling of pump casing reveals the overall flow pattern and pressure distribution, a complete 3D model of pump casing is essential to fully capture the interaction of the primary main stream flow and the secondary flows especially in areas of heavy recirculation. This paper presents steady state finite element simulation of multi-size particulate slurry flow through three dimensional pump casing. The flow field and concentration distribution is presented for different cross-sectional planes. The multi-size particulate flow simulation results are compared with two mono-size particle simulations using (1) the concentration weighted mean diameter of the slurry and (b) the D50 size of the slurry. Qualitative comparison is made with the wear rate predicted by the simulations and the field data. Simulations and field data show that at low flow rates, the side-wall gouging wear near the tongue region becomes significant.
6

Matthew Evans, T., and Jeremy Kress. "Discrete Simulations of Particulate-Structure Interactions." In Geo-Frontiers Congress 2011. Reston, VA: American Society of Civil Engineers, 2011. http://dx.doi.org/10.1061/41165(397)435.

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7

Walther, Jens H., Julian T. Sagredo, and Petros Koumoutsakos. "SIMULATION OF PARTICULATE FLOWS USING VORTEX METHODS." In Selected Papers of the First International Conference on Vortex Methods. WORLD SCIENTIFIC, 2000. http://dx.doi.org/10.1142/9789812793232_0020.

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8

Hao, Zuoxin. "CFD Simulation of Segregation in Particulate Multiphase Flows With Binary Solids." In ASME 2005 Fluids Engineering Division Summer Meeting. ASMEDC, 2005. http://dx.doi.org/10.1115/fedsm2005-77375.

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Segregation in particulate multiphase flow with binary solid mixture has extensive applications in industrial separation processes. Up to now there have been few attempts towards numerical simulation of segregation in particulate multiphase flow with binary mixture due to complexity of the problem. In view of this, the primary objective of present work is to simulate the problem by computational fluid dynamics (CFD) and to validate by comparison with experimental measurements. Eulerian-Eulerian approach, incorporating the granular temperature, an essential ingredient in the solids pressure and solids viscosity formulation, was used to model the flow field of multiphase flow and was solved by Fluent 6.0. The CFD simulation results have been validated by experiments of liquid fluidization of binary solid mixtures. Validation results show that CFD simulation predict segregation and solid volume fraction profile precisely, and in addition, it can supply a more realistic prediction of other hydrodynamic features of the multiphase flow, such as velocity vector of all phases and pressure drop. The success of such CFD simulations opens doors for many potential studies.
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Shimazaki, Yasuhiro. "Three-dimensional Numerical Simulation of Gas-particulate Flow around Breathing Human and Particulate Inhalation." In FLOW DYNAMICS: The Second International Conference on Flow Dynamics. AIP, 2006. http://dx.doi.org/10.1063/1.2204538.

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Acri, A., M. Kronbichler, A. Garcia, P. Díez, and W. Wall. "On Solid-Fluid Mixture Models for High Particulate Volume Fractions." In 10th International Conference on Adaptative Modeling and Simulation. CIMNE, 2021. http://dx.doi.org/10.23967/admos.2021.065.

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Звіти організацій з теми "Simulation particulaire":

1

Pullammanappallil, Pratap, Haim Kalman, and Jennifer Curtis. Investigation of particulate flow behavior in a continuous, high solids, leach-bed biogasification system. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600038.bard.

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Recent concerns regarding global warming and energy security have accelerated research and developmental efforts to produce biofuels from agricultural and forestry residues, and energy crops. Anaerobic digestion is a promising process for producing biogas-biofuel from biomass feedstocks. However, there is a need for new reactor designs and operating considerations to process fibrous biomass feedstocks. In this research project, the multiphase flow behavior of biomass particles was investigated. The objective was accomplished through both simulation and experimentation. The simulations included both particle-level and bulk flow simulations. Successful computational fluid dynamics (CFD) simulation of multiphase flow in the digester is dependent on the accuracy of constitutive models which describe (1) the particle phase stress due to particle interactions, (2) the particle phase dissipation due to inelastic interactions between particles and (3) the drag force between the fibres and the digester fluid. Discrete Element Method (DEM) simulations of Homogeneous Cooling Systems (HCS) were used to develop a particle phase dissipation rate model for non-spherical particle systems that was incorporated in a two-fluid CFDmultiphase flow model framework. Two types of frictionless, elongated particle models were compared in the HCS simulations: glued-sphere and true cylinder. A new model for drag for elongated fibres was developed which depends on Reynolds number, solids fraction, and fibre aspect ratio. Schulze shear test results could be used to calibrate particle-particle friction for DEM simulations. Several experimental measurements were taken for biomass particles like olive pulp, orange peels, wheat straw, semolina, and wheat grains. Using a compression tester, the breakage force, breakage energy, yield force, elastic stiffness and Young’s modulus were measured. Measurements were made in a shear tester to determine unconfined yield stress, major principal stress, effective angle of internal friction and internal friction angle. A liquid fludized bed system was used to determine critical velocity of fluidization for these materials. Transport measurements for pneumatic conveying were also assessed. Anaerobic digestion experiments were conducted using orange peel waste, olive pulp and wheat straw. Orange peel waste and olive pulp could be anaerobically digested to produce high methane yields. Wheat straw was not digestible. In a packed bed reactor, anaerobic digestion was not initiated above bulk densities of 100 kg/m³ for peel waste and 75 kg/m³ for olive pulp. Interestingly, after the digestion has been initiated and balanced methanogenesis established, the decomposing biomass could be packed to higher densities and successfully digested. These observations provided useful insights for high throughput reactor designs. Another outcome from this project was the development of low cost devices to measure methane content of biogas for off-line (US$37), field (US$50), and online (US$107) applications.
2

Bauer, Andrew. In situ and time. Engineer Research and Development Center (U.S.), December 2022. http://dx.doi.org/10.21079/11681/46162.

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Large-scale HPC simulations with their inherent I/O bottleneck have made in situ visualization an essential approach for data analysis, although the idea of in situ visualization dates back to the era of coprocessing in the 1990s. In situ coupling of analysis and visualization to a live simulation circumvents writing raw data to disk for post-mortem analysis -- an approach that is already inefficient for today's very large simulation codes. Instead, with in situ visualization, data abstracts are generated that provide a much higher level of expressiveness per byte. Therefore, more details can be computed and stored for later analysis, providing more insight than traditional methods. This workshop encouraged talks on methods and workflows that have been used for large-scale parallel visualization, with a particular focus on the in situ case.
3

Hayashi, Hidemitsu, and Shuichi Kubo. Computer Simulation Study on Deposition of Soot Particles in Diesel Particulate Filter. Warrendale, PA: SAE International, September 2005. http://dx.doi.org/10.4271/2005-08-0496.

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4

Krispin, Jacob, Mark Potts, Brady Brown, Ralph Ferguson, and James Collins. High-Order Godunov Schemes for Multiphase Gas-Particulate Flowfield Modeling and Simulation. Fort Belvoir, VA: Defense Technical Information Center, September 2000. http://dx.doi.org/10.21236/ada385335.

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5

Semerikov, Serhiy O., Illia O. Teplytskyi, Yuliia V. Yechkalo, and Arnold E. Kiv. Computer Simulation of Neural Networks Using Spreadsheets: The Dawn of the Age of Camelot. [б. в.], November 2018. http://dx.doi.org/10.31812/123456789/2648.

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The article substantiates the necessity to develop training methods of computer simulation of neural networks in the spreadsheet environment. The systematic review of their application to simulating artificial neural networks is performed. The authors distinguish basic approaches to solving the problem of network computer simulation training in the spreadsheet environment, joint application of spreadsheets and tools of neural network simulation, application of third-party add-ins to spreadsheets, development of macros using the embedded languages of spreadsheets; use of standard spreadsheet add-ins for non-linear optimization, creation of neural networks in the spreadsheet environment without add-ins and macros. After analyzing a collection of writings of 1890-1950, the research determines the role of the scientific journal “Bulletin of Mathematical Biophysics”, its founder Nicolas Rashevsky and the scientific community around the journal in creating and developing models and methods of computational neuroscience. There are identified psychophysical basics of creating neural networks, mathematical foundations of neural computing and methods of neuroengineering (image recognition, in particular). The role of Walter Pitts in combining the descriptive and quantitative theories of training is discussed. It is shown that to acquire neural simulation competences in the spreadsheet environment, one should master the models based on the historical and genetic approach. It is indicated that there are three groups of models, which are promising in terms of developing corresponding methods – the continuous two-factor model of Rashevsky, the discrete model of McCulloch and Pitts, and the discrete-continuous models of Householder and Landahl.
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Peter J. Mucha. Final Report: Model interacting particle systems for simulation and macroscopic description of particulate suspensions. Office of Scientific and Technical Information (OSTI), August 2007. http://dx.doi.org/10.2172/939459.

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7

Dodd, Brandon, Osama Ennasr, Amir Naser, Charles Ellison, Jason Ray, Garry Glaspell, and Anton Netchaev. Mapping and localization within a mock sewer system. Engineer Research and Development Center (U.S.), September 2023. http://dx.doi.org/10.21079/11681/47616.

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Herein, we explored a robot’s ability to localize and map, both in simulation and on a physical robot, within a mock sewer system. Mapping and localization techniques were first developed and tested in simulation and were then transitioned to the actual robot for additional physical testing. Several odometry and simultaneous localization and mapping (SLAM) techniques, including gmapping, SLAM toolbox, elevation mapping, and RTABMap, were evaluated for this particular environment. The results of the odometry and the various SLAM approaches are discussed in detail.
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Boysen-Urban, Kirsten, Hans Grinsted Jensen, and Martina Brockmeier. Extending the GTAP Data Base and Model to Cover Domestic Support Issues using the EU as Example. GTAP Technical Paper, June 2014. http://dx.doi.org/10.21642/gtap.tp35.

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The EU Single Farm Payment (SFP) is currently distributed in proportion to primary factor shares in version 8 of the GTAP database. In this paper, we investigate whether this way of modeling the EU SFP makes a difference in analyzing agricultural policy reforms. To do so, we create alternative versions of the GTAP database to compare the effects with the default setting in GTAP. Employing OECD data, along with the GTAP framework, we vary the assumptions about the allocation of the SFP. In the process, we demonstrate how to alter and update the GTAP database to implement domestic support of OECD PSE tables. We provide a detailed overview supplemented with assumptions of payment allocation, shock calculations and in particular, the Altertax procedure to update value flows and price equations extended in the GTAP model. Subsequently, we illustrate the impact of those assumptions by simulating a 100% removal of the SFP using the deviating versions of GTAP database. This sensitivity analysis reveals strong differences in results, but particularly in production responses of food and agricultural sectors that decrease with an increasing degree of decoupling. Furthermore, our analysis shows that the effect on welfare and the trade balance decreases with an increasing degree of decoupling. This experiment shows that the allocation of the SFP can have strong impacts on simulation results.
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Vergara, Rodrigo, and Sebastián Edwards. Fiscal Sustainability, Debt Dynamics and Debt Relief: The Cases of Nicaragua and Honduras. Inter-American Development Bank, December 2002. http://dx.doi.org/10.18235/0009172.

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The purpose of this paper is to analyze the relationship between fiscal policy, aggregate public sector debt sustainability, and debt relief. In particular, we develop a methodology to compute the fiscal policy path that is compatible with aggregate debt sustainability in the post-HIPC era (Highly Indebted Poor Countries relief initiative). This model explicitly considers the role of domestic debt, and quantifies the extent to which future debt sustainability depends on the availability of concessional loans at subsidized interest rates. The working of the model is illustrated for the cases of Honduras and Nicaragua. Both countries differ markedly in terms of the burdens of their external and internal debts. The results from our simulation analysis indicate that unless Nicaragua receives substantial concessional aid in the future, its public sector debt is likely to become unsustainable. In the case of Honduras, our simulation exercise shows that under reasonable parameters the country's fiscal stance as of 2001 is sustainable.
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Daniellou, François. Taking account of human and organisational factors in planning and designing a high risk system. Fondation pour une culture de sécurité industrielle, July 2021. http://dx.doi.org/10.57071/381ynz.

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A Human and Organisational Factors (HOF) approach to project planning and design aims to improve decisions by anticipating the consequences of technical and organisational choices on the human activity that will take place in future operations. To foster efficient and safe work, the HOF approach is based on in-depth analysis of human activity in existing situations combined with simulation of probable activity in future operations, based on planned technical and organisational choices. The approach requires project owners to express their requirements clearly, good coordination with design and engineering contractors, and participation of various stakeholders, in particular from operations. The integration of a HOF approach should start at Front End Engineering and continue until the final project review.

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