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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

IMPLEMENTATION AND VALIDATION OF THE HYBRID TURBULENCE MODELS IN AN UNSTRUCTURED GRID CODE

Panguluri, Sri S. 01 January 2007 (has links)
Since its introduction in 1997, the use of Detached Eddy Simulation (DES) and similar hybrid turbulence techniques has become increasingly popular in the field of CFD. However, with increased use some of the limitations of the DES model have become apparent. One of these is the dependence of DES on grid construction, particularly regarding the point of transition between the Reynolds-Averaged Navier-Stokes and Large Eddy Simulation models. An additional issue that arises with unstructured grids is the definition of the grid spacing in the implementation of a DES length scale. To lay the ground work to study these effects the Spalart-Allmaras one-equation turbulence model, SA based DES hybrid turbulence model, and the Scale Adaptive Simulation hybrid turbulence model are implemented in an unstructured grid CFD code, UNCLE. The implemented SA based DES model is validated for flow over a three-dimensional circular cylinder for three different turbulent Reynolds numbers. Validation included studying the pressure, skin friction coefficient, centerline velocity distributions averaged in time and space. Tools to output the mean velocity profiles and Reynolds stresses were developed. A grid generation code was written to generate a two/three dimensional circular cylinder grid to simulate flow over the cylinder in UNCLE. The models implemented and validated, and the additional tools mentioned will be used in the future.
2

Multikriterielle Simulation und Optimierung im Leichtbau

Kroll, Lothar, Ulke-Winter, Lars 10 July 2015 (has links)
Das Hauptanliegen des Bundesexellenzclusters MERGE: Technologiefusion für multifunktionale Leichtbaustrukturen ist die Verwendung von prozesstauglichen Technologien zur resourceneffizienten Herstellung von Leichtbaustrukturen in Mischbauweise. In der Interactive Domain (IRD): Modelling, Integrative Simulation and Optimization des Cluster of Excellence „MERGE“ werden ganzheitliche und durchgängige Simulationsketten entwickelt, um das Werkstoffverhalten von unterschiedlichen Materialgruppen unter Berücksichtigung prozessbedingter und belastungsspezifischer Restriktionen aufeinander abzustimmen. Die Bauteileigenschaften und Randbedingungen bei der Herstellung der Hybridbauteile hängen dabei, neben den verwendeten Materialkombinationen (Kunststoffe, Faserverbunde, Metalle), in starkem Maße von den zugrundeliegenden Fertigungsprozessen ab. Insbesondere die multikriterielle Optimierung -- von der Herstellung bis zum belasteten Bauteil -- benötigt eine Vielzahl an aufwändigen Simulationen die ein effizientes Datenmanagement sowie verteilten Berechnungsumgebungen erfordern. / The main objective of the Cluster of Excellence “MERGE”: Merge Technologies for Multifunctional Lightweight Structures is the use of process technologies suitable for resource-efficient production of lightweight structures in composite design. In the Interactive Research Domain (IRD): Modelling, Simulation and Optimization of Cluster of Excellence "MERGE" holistic and integrated simulation chains are designed to match the material behavior of different groups of materials under consideration of process-related and load specific restrictions. The component properties and constraints in the production of hybrid components depend in addition to the used material combinations (fiber reinforced plastics and metals) largely on the underlying production process. In particular, the multicriteria optimization - from manufacturing process until the loaded lightweight structure -- requires a large number of complex simulations which require an efficient data management and distributed computing environments.
3

3D modeling of city building and lifecycle simulation / Modélisation 3D du bâtiment urbain et simulation du cycle de vie

Zhu, Wenhua 28 March 2017 (has links)
Avec la construction et le développement de la ville intelligente, la façon de construire le modèle 3D réaliste des grands bâtiments de la ville rapidement et efficacement devient le hotspot de recherche. Dans cette thèse, une méthode procédurale de modélisation intelligente est proposée pour construire rapidement et efficacement un modèle de construction de ville 3D à grande échelle basé sur la modélisation de la forme de la façade et de la grammaire de forme. La technologie de l'information du bâtiment (BIM) est un moyen technique important pour améliorer l'industrie de la construction, pour la conception du bâtiment de la ville et la construction de la meilleure recherche et l'application de la technologie BIM est la clé, de gérer efficacement les informations du cycle de vie du bâtiment et de réaliser le partage et l'échange. Cette thèse a étudié l'acquisition et le traitement des données de modélisation. Google Earth et le logiciel ArcGIS sont principalement utilisés pour acquérir et traiter des données d'images-cartes et des données de cartes d'élévation de la zone cible, ces deux types de correspondance et de superposition de données, qui peuvent générer des données de terrain urbain 3D avec des informations de localisation géographique. Ensuite OpenStreetMap est utilisé pour acquérir les données routières de la zone cible, et il peut être optimisé pour le réseau routier nécessaire par le logiciel JOSM. La technologie de balayage laser 3D est utilisée pour collecter des images de texture de surface de bâtiment et pour créer le modèle de nuages de points de la modélisation d'architecture cible afin d'obtenir les dimensions de modélisation par mesure. Sur cette base, cette thèse a principalement étudié le principe et le processus de la règle CGA pour créer des modèles de construction, et étudié la méthode qui peut séparer les éléments architecturaux en utilisant la segmentation d'image pour générer automatiquement la règle CGA et de créer ensuite le modèle de construction. Ainsi, des modèles de construction 3D ont été établis dans le logiciel CityEngine en utilisant les règles CGA et la technologie de segmentation des façades. Cette thèse a construit le modèle d'information intégré au bâtiment urbain (CBIIM) basé sur BIM. L'information sur la construction de la ville est classée et intégrée, et le bâtiment et la composante ont été décrits avec la norme IFC, afin de gérer efficacement les informations du cycle de vie du bâtiment. Cette thèse étudie la technologie du modèle d'association d'information intégrée, qui permet de réaliser une conception standardisée des composants avec des caractéristiques associées et une conception intelligente des bâtiments avec des paramètres associés dans les règles de connaissances combinées avec l'IFC. La technologie de simulation de la construction de visualisation est étudiée. Les règles de connaissance dans le modèle d'information intégré fournissent une référence fiable pour la simulation de construction, et la scène de simulation est créée en invoquant le modèle d'information intégré, ainsi le processus de simulation est terminé. En prenant le campus Baoshan de l'Université de Shanghai comme exemple, le processus de modélisation de la scène entière est illustré, et les étapes de modélisation de toutes sortes d'objets 3D sont décrites en détail pour résoudre les problèmes spécifiques dans le processus de modélisation réelle. Ainsi, la faisabilité et la validité de la méthode de modélisation intelligente procédurale sont vérifiées. Prenant comme exemple le dortoir de l'Université de Shanghai, une simulation et le modèle de simulation ont été créés par les informations intégrées, combinées aux informations de construction pertinentes, la simulation de construction a été complétée par le programme. Ainsi, la faisabilité et la validité du CBIIM sont vérifiées. / With the construction and development of the smart city, how to construct the realistic 3D model of the large-scale city buildings quickly and efficiently which becomes the research hotspot. In this thesis, a novel 3D modeling approach is proposed to quickly and efficiently build 3D model of large-scale city buildings based on shape grammar and facade rule modeling. Building Information Model (BIM) is an important technical means to enhance the construction industry, for the city building design and construction, how to better research and application of BIM technology which is the key, in this thesis City Building Integrated Information Model (CBIIM) is specified to manage the information of building lifecycle effectively and realize the information sharing and exchanging. This thesis has studied the acquisition and processing of the modeling data. Google Earth and ArcGIS software are mainly used to acquire and process image-maps data and elevation-maps data of the target area, these two kinds of data match and overlay, which can generate 3D city terrain data with geographic location information. Then OpenStreetMap is used to acquire road data of the target area, and it can be optimal processed to the necessary road network by JOSM software. 3D laser scanning technology is used to collect building surface texture images and create the point clouds model of the target architecture modeling so as to get the modeling dimensions by measurement. On this basis, this thesis mainly has studied the principle and the process of CGA rule to create building models, and studied the method that can separate architectural elements using image segmentation to generate CGA rule automatically and to create building model furtherly. Thus 3D building models have been established in the CityEngine software using CGA rules and facade modeling technology. This thesis has specified the City Building Integrated Information Model (CBIIM) based on BIM. The city building information are classified and integrated, and the building and component was described with the IFC standard, in order to manage the informations of building lifecycle effectively. This thesis studies the integrated information association model technology, that it can realize standardized component design with associated features and intelligent building design with associated parameters in knowledge rules combined with IFC. The construction simulation technology is studied. The knowledge rules in the integrated information model provide a reliable reference for the construction simulation, and the simulation scene is created through the invoking the integrated information model, thus the construction simulation process is completed by the program. Taking Baoshan Campus of Shanghai University as an example, the modeling process of the whole scene is illustrated, and the modeling steps of all kinds of 3D objects are described in detail to solve the specific problems in the actual modeling process. Thus the feasibility and validity of the procedural intelligent modeling approach are verified. Taking the dormitory of Shanghai University as an example, a simulation scene and the simulation model were created by the integrated informations, combined with the relevant construction information the construction simulation was completed by the program. Thus the feasibility and validity of the CBIIM are verified.
4

Analýza řadicího mechanizmu traktoru / Tractor Shift Mechanism Analysis

Netopil, Jan January 2021 (has links)
The thesis focuses on the shifting mechanisms of manually shifted tractor transmissions. It provides a comprehensive overview of all significant structural nodes of the shift mechanism with an analysis of the influence of the structure on the resulting intensity of a force required for shifting. The main aim of this thesis is the design and validation of experimental equipment for measuring the force effects of the shift mechanism of a mass-produced tractor in actual operation. The design of the experimental equipment is based on a study of the used measuring technique and similar experimental equipment. The final structure is selected based on selection by the method of weighted values, taking into consideration the requirements of the structure. A functional measuring chain is designed and formed for the realization of the measurement. To evaluate the data from the technical experiment, a multibody model of the designed experimental device is created in the MSC Adams View software, through which the real parameters of the shift mechanism are obtained from the measured values. The designed experimental equipment brings the possibility of complete analysis and subsequent optimization of the tractor's shift mechanism
5

Stavebně technologický projekt výjezdové základny zdravotnické záchranné služby v Zábřehu na Moravě / CONSTRUCTION AND TECHNOLOGICAL PROJECT OF THE BASE OF THE EMERGENCY MEDICAL SERVICE IN ZABREH NA MORAVE

Tůma, František January 2019 (has links)
This diploma thesis deals with the construction project of the outbound base of the emergency medical service in Zabreh na Morave. More specifically, this thesis deals with the study of the development of the building, the technological regulation for the flat roof, and the subsequent chapters - design and assessment of the lifting mechanism, optimal design of the building site, timetable, itemized budget, control and test plan, etc. An interesting point is the simulation of the construction, where a 3D model and a video are created. The thesis is based on a borrowed documentation of the project.

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