Дисертації з теми "Multi-fidelity models"
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Benamara, Tariq. "Full-field multi-fidelity surrogate models for optimal design of turbomachines." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2368.
Повний текст джерелаOptimizing turbomachinery components stands as a real challenge despite recent advances in theoretical, experimental and High-Performance Computing (HPC) domains. This thesis introduces and validates optimization techniques assisted by full-field Multi-Fidelity Surrogate Models (MFSMs) based on Proper Orthogonal Decomposition (POD). The combination of POD and Multi-Fidelity Modeling (MFM) techniques allows to capture the evolution of dominant flow features with geometry modifications. Two POD based multi-fidelity optimization methods are proposed. Thefirst one consists in an enrichment strategy dedicated to Gappy-POD (GPOD)models. It is more suitable for instantaneous low-fidelity computations whichmakes it hardly tractable for aerodynamic design of turbomachines. This methodis demonstrated on the flight domain study of a 2D airfoil from the literature. The second methodology is based on a multi-fidelity extension to Non-IntrusivePOD (NIPOD) models. This extension starts with a re-interpretation of theConstrained POD (CPOD) concept and allows to enrich the reduced spacedefinition with abondant, albeit inaccurate, low-fidelity information. In the second part of the thesis, a benchmark test case is introduced to test fullfield multi-fidelity optimization methodologies on an example presenting featuresrepresentative of turbomachinery problems. The predictability of the proposedMulti-Fidelity NIPOD (MFNIPOD) surrogate models is compared to classical surrogates from the literature on both analytical and industrial-scale applications. Finally, we employ the proposed tool to the shape optimization of a 1.5-stage boosterand we compare the obtained results with standard state of the art approaches
Belben, Joel Brian. "ENABLING RAPID CONCEPTUAL DESIGN USING GEOMETRY- BASED MULTI-FIDELITY MODELS IN VSP." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/969.
Повний текст джерелаHebert, James L. "Use of Multi-Fidelity and Surrogate Models to Reduce the Cost of Developing Physics-Based Systems." Thesis, The George Washington University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3687685.
Повний текст джерелаBuilding complex physics-based systems in a timely cost-effective manner, that perform well, meet diverse user needs, and have no bad emergent behaviors is a challenge. To meet these requirements the solution is to model the physics-based system before building it. Modeling and Simulation capabilities for these type systems have advanced continuously during the past 20 years thanks to progress in the application of high fidelity computational codes that are able to model the real physical performance of system components. The problem is that it is often too time consuming and costly to model complex systems, end-to-end, using these high fidelity computational models alone. Missing are good approaches to segment the modeling of complex systems performance and behaviors, keep the model chain coherent and only model what is necessary. Current research efforts have shown that using multi-fidelity and/or surrogate models might offer alternative methods of performing the modeling and simulations needed to design and develop physics-based systems more efficiently. This study demonstrates that it is possible reduce the number of high fidelity runs allowing the use of classical systems engineering analysis and tools that would not be possible if only high fidelity codes were employed. This study advances the systems engineering of physics-based systems by reducing the number of time consuming high fidelity models and simulations that must be used to design and develop the systems. The study produced a novel approach to the design and development of complex physics-based systems by using a mix of variable fidelity physics-based models and surrogate models. It shows that this combination of increasing fidelity models enables the computationally and cost efficient modeling and simulation of these complex systems and their components. The study presents an example of the methodology for the analysis and design of two physics-based systems: a Ground Penetrating Radar (GPR) and a Nuclear Electromagnetic Pulse Bounded Wave System.
Raub, Corey Bevan. "Geometric analysis of axisymmetric disk forging." Ohio : Ohio University, 2000. http://www.ohiolink.edu/etd/view.cgi?ohiou1172778393.
Повний текст джерелаAulmann, Maria. "Entwicklung und Evaluierung von Clinical Skills - Simulatoren für die Lehre in der Tiermedizin." Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-215224.
Повний текст джерелаIntroduction Students of veterinary medicine are expected to acquire various practical skills in addition to a wide range of theoretical knowledge. There is a strong demand for training opportunities, as every individual learns and acquires practical skills at individual pace. For reasons of animal welfare concerns and availability, live animals and cadavers cannot always be used for clinical skills training. Simulation models, which are models of organisms or body parts can be a considerable alternative for clinical skills training. Models that are commercially produced often have a high price and are not available for all skills. Self-made models are increasingly used in veterinary education. Because there is few published data regarding their use, more scientific research is required. Aims of the Investigation The objective of this study was to determine, if self-made low-fidelity models can be successfully used in veterinary medical education. For this purpose, two self-made low-fidelity models were evaluated (study 1) and their use in combination with other teaching tools was analyzed (study 2). Materials and Methods In study 1, two self-made low-fidelity models for simulation of canine intubation and canine female urinary catheterization were developed and evaluated. We used a study design that compares acquired skills of two intervention groups and one control group in a practical examination (OSCE = objective structured clinical examination). Fifty-eight second-year veterinary medicine students received a theoretical introduction to intubation and were randomly divided into three groups. Group 1 (high-fidelity) was then trained on a commercially available Intubation Training Manikin, group 2 (low-fidelity) was trained on our low-fidelity model, and the text group read a text describing intubation of the dog. Forty-seven fifth-year veterinary medicine students followed the same procedure for training urinary catheterization using the commercially available Female Urinary Catheter Training Manikin, our self-made model, and text. Outcomes were assessed in a practical examination on a cadaver using an OSCE checklist. In study 2 we evaluated the teaching of two specific clinical skills using potcasts and low-fidelity simulation training. Two instructional potcasts describing intubation and catheterization and both low-fidelity models described above were used. In our study, potcasts are audio-visual animations that provide the learner with step by step information and instruction on a clinical skill. We used a crossover study design and compared the acquired practical skills of two intervention groups after a different theoretical preparation. A survey captured the participants’ feedback. Sixty first year veterinary medicine students were randomly allocated to two groups, a potcast group and a text group. The potcast group watched a potcast while the text group read an instructional text for preparation. Then both groups had separate self-directed training sessions on low-fidelity models. Outcomes were assessed in practical examinations on a cadaver using an objective structured clinical examination (OSCE) checklist. Results In study 1 all intervention groups performed significantly better than the text groups. Group I (high-fidelity) and group II (low-fidelity) for both intubation and catheterization showed no significant differences. In study 2 the potcast group performed significantly better than the text group in study intubation but no significant differences were observed in study catheterization. Overall, participants enjoyed clinical skills training but experienced self-directed learning as challenging. Conclusion Low-fidelity models can be as effective as high-fidelity models for clinical skills training. Clinical skills training using potcasts and self-directed low-fidelity simulation training should be complemented by supervisor or peer instruction rather than used as exclusive tool for teaching first year veterinary students. We assume though, that self-directed learning instructed by our potcasts can be a valuable chance for deepening and repetitive training of higher semesters. The use of simulation models in veterinary education has been consistently increasing in the past few years. This study is an important, timely contribution to the evaluation of simulation based education
Biehler, Jonas [Verfasser], Wolfgang A. [Akademischer Betreuer] [Gutachter] Wall, and Phaedon-Stelios [Gutachter] Koutsourelakis. "Efficient Uncertainty Quantification for Large-Scale Biomechanical Models Using a Bayesian Multi-Fidelity Approach / Jonas Biehler ; Gutachter: Wolfgang A. Wall, Phaedon-Stelios Koutsourelakis ; Betreuer: Wolfgang A. Wall." München : Universitätsbibliothek der TU München, 2016. http://d-nb.info/1123729220/34.
Повний текст джерелаSacher, Matthieu. "Méthodes avancées d'optimisation par méta-modèles – Applicationà la performance des voiliers de compétition." Thesis, Paris, ENSAM, 2018. http://www.theses.fr/2018ENAM0032/document.
Повний текст джерелаSailing yacht performance optimization is a difficult problem due to the high complexity of the mechanicalsystem (aero-elastic and hydrodynamic coupling) and the large number of parameters to optimize (sails, rigs, etc.).Despite the fact that sailboats optimization is empirical in most cases today, the numerical optimization approach is nowconsidered as possible because of the latest advances in physical models and computing power. However, these numericaloptimizations remain very expensive as each simulation usually requires solving a non-linear fluid-structure interactionproblem. Thus, the central objective of this thesis is to propose and to develop original methods aiming at minimizing thenumerical cost of sailing yacht performance optimization. The Efficient Global Optimization (EGO) is therefore appliedto solve various optimization problems. The original EGO method is extended to cases of optimization under constraints,including possible non computable points, using a classification-based approach. The use of multi-fidelity surrogates isalso adapted to the EGO method. The applications treated in this thesis concern the original optimization problems inwhich the performance is modeled experimentally and/or numerically. These various applications allow for the validationof the developments in optimization methods on real and complex problems, including fluid-structure interactionphenomena
Chetry, Manisha. "Advanced reduced-order modeling and parametric sampling for non-Newtonian fluid flows." Electronic Thesis or Diss., Ecole centrale de Nantes, 2023. http://www.theses.fr/2023ECDN0011.
Повний текст джерелаThe subject of this thesis concernsmodel-order reduction (MOR) of parameterizednon-Newtonian flow problems that havesignificant industrial applications. TraditionalMOR methods constrain the computationalperformance of such highly nonlinear problems,so we suggest a state-of-the-art hyper-reductiontechnique based on a sparse approximation totackle the evaluation of nonlinear terms at muchreduced complexity. We also provide offlinestabilization strategy for stabilizing theconstitutive model in the reduced order modelframework that is less expensive to computewhile maintaining the full order model's (FOM)accuracy. Combining the two significantlylowers the CPU cost as compared to the FOMevaluation which inevitably boosts MORperformance. This work is validated on twobenchmark flow problems. Additionally, anadaptive sampling strategy is also presented inthis manuscript which is achieved byleveraging multi-fidelity model approximation.Towards the end of the thesis, we addressanother issue that is typically observed forcases when adaptive finite element meshesare deployed. In such cases, MOR methods failto produce a low-dimensional representationsince the snapshots are not vectors of samelength. We therefore, suggest an alternatemethod that can generate reduced basisfunctions for database of space-adaptedsnapshots
Eaton, Ammon Nephi. "Multi-Fidelity Model Predictive Control of Upstream Energy Production Processes." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6376.
Повний текст джерелаMAININI, LAURA. "Multidisciplinary and multi-fidelity optimization environment for wing integrated design." Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2500000.
Повний текст джерелаCzechowicz, Maciej P. "Analysis of vehicle rollover using a high fidelity multi-body model and statistical methods." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/18106.
Повний текст джерелаCheng, Si. "Hierarchical Nearest Neighbor Co-kriging Gaussian Process For Large And Multi-Fidelity Spatial Dataset." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613750570927821.
Повний текст джерелаStults, Ian Collier. "A multi-fidelity analysis selection method using a constrained discrete optimization formulation." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31706.
Повний текст джерелаCommittee Chair: Mavris, Dimitri; Committee Member: Beeson, Don; Committee Member: Duncan, Scott; Committee Member: German, Brian; Committee Member: Kumar, Viren. Part of the SMARTech Electronic Thesis and Dissertation Collection.
Hayek, Michael Elia. "Adjoint-based optimization of U-bend channel flow using a multi-fidelity eddy viscosity turbulence model." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112423.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 177-180).
Many fluid flows in engineering are turbulent and require the use of computational fluid dynamics (CFD) for design purposes. Optimization with CFD has largely been limited to low-fidelity simulation methods, such as Reynolds Averaged Navier Stokes (RANS), due to current computational capabilities. However, RANS has been shown to lack sufficient accuracy for certain flows. This thesis presents CFD simulation of a 180 degree U-bend square duct using low-fidelity steady RANS and high-fidelity wall-resolved Large Eddy Simulation (LES) models. The LES solution is shown to match experimental results, whereas the RANS solution is not sufficiently accurate. A process for training a RANS eddy viscosity field using the LES solution is provided. This approach is based on solving an inference problem by comparing the RANS calculations to the LES solution and tuning cell-based turbulent viscosity values. This multi-fidelity framework is intended to highlight that high-fidelity solutions can be used to improve even the simplest RANS turbulence models. The adjoint method is used for efficient gradient-based optimization of the turbulent viscosity on a U-bend channel to minimize the velocity solution error. Other objective functions are explored to check the uniqueness of the optimized turbulent viscosity. Sensitivity of the optimized result to the numerical convection scheme is presented to help provide insight for future optimization of turbulence models. The optimized turbulent viscosity is also used on a modified U-bend channel to demonstrate the applicability of the method on new geometries.
by Michael Elia Hayek.
S.M.
Austin, Jason Louis. "A Multi-Component Analysis of a Wind Turbine Gearbox Using a High Fidelity Finite Element Model." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1370441712.
Повний текст джерелаOksuz, Ozhan. "Multiploid Genetic Algorithms For Multi-objective Turbine Blade Aerodynamic Optimization." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609196/index.pdf.
Повний текст джерелаCrowley, Daniel R. "An efficient approach for high-fidelity modeling incorporating contour-based sampling and uncertainty." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50382.
Повний текст джерелаMeng, Fanzi. "Multi-fidelity sparse-grid-based surrogate models." Master's thesis, 2020. http://hdl.handle.net/1885/212851.
Повний текст джерелаAulmann, Maria. "Entwicklung und Evaluierung von Clinical Skills - Simulatoren für die Lehre in der Tiermedizin." Doctoral thesis, 2015. https://ul.qucosa.de/id/qucosa%3A15144.
Повний текст джерелаIntroduction Students of veterinary medicine are expected to acquire various practical skills in addition to a wide range of theoretical knowledge. There is a strong demand for training opportunities, as every individual learns and acquires practical skills at individual pace. For reasons of animal welfare concerns and availability, live animals and cadavers cannot always be used for clinical skills training. Simulation models, which are models of organisms or body parts can be a considerable alternative for clinical skills training. Models that are commercially produced often have a high price and are not available for all skills. Self-made models are increasingly used in veterinary education. Because there is few published data regarding their use, more scientific research is required. Aims of the Investigation The objective of this study was to determine, if self-made low-fidelity models can be successfully used in veterinary medical education. For this purpose, two self-made low-fidelity models were evaluated (study 1) and their use in combination with other teaching tools was analyzed (study 2). Materials and Methods In study 1, two self-made low-fidelity models for simulation of canine intubation and canine female urinary catheterization were developed and evaluated. We used a study design that compares acquired skills of two intervention groups and one control group in a practical examination (OSCE = objective structured clinical examination). Fifty-eight second-year veterinary medicine students received a theoretical introduction to intubation and were randomly divided into three groups. Group 1 (high-fidelity) was then trained on a commercially available Intubation Training Manikin, group 2 (low-fidelity) was trained on our low-fidelity model, and the text group read a text describing intubation of the dog. Forty-seven fifth-year veterinary medicine students followed the same procedure for training urinary catheterization using the commercially available Female Urinary Catheter Training Manikin, our self-made model, and text. Outcomes were assessed in a practical examination on a cadaver using an OSCE checklist. In study 2 we evaluated the teaching of two specific clinical skills using potcasts and low-fidelity simulation training. Two instructional potcasts describing intubation and catheterization and both low-fidelity models described above were used. In our study, potcasts are audio-visual animations that provide the learner with step by step information and instruction on a clinical skill. We used a crossover study design and compared the acquired practical skills of two intervention groups after a different theoretical preparation. A survey captured the participants’ feedback. Sixty first year veterinary medicine students were randomly allocated to two groups, a potcast group and a text group. The potcast group watched a potcast while the text group read an instructional text for preparation. Then both groups had separate self-directed training sessions on low-fidelity models. Outcomes were assessed in practical examinations on a cadaver using an objective structured clinical examination (OSCE) checklist. Results In study 1 all intervention groups performed significantly better than the text groups. Group I (high-fidelity) and group II (low-fidelity) for both intubation and catheterization showed no significant differences. In study 2 the potcast group performed significantly better than the text group in study intubation but no significant differences were observed in study catheterization. Overall, participants enjoyed clinical skills training but experienced self-directed learning as challenging. Conclusion Low-fidelity models can be as effective as high-fidelity models for clinical skills training. Clinical skills training using potcasts and self-directed low-fidelity simulation training should be complemented by supervisor or peer instruction rather than used as exclusive tool for teaching first year veterinary students. We assume though, that self-directed learning instructed by our potcasts can be a valuable chance for deepening and repetitive training of higher semesters. The use of simulation models in veterinary education has been consistently increasing in the past few years. This study is an important, timely contribution to the evaluation of simulation based education.
Melani, Pier Francesco. "Power augmentation of Darrieus-type turbines by means of novel solutions and multi-fidelity simulations." Doctoral thesis, 2022. http://hdl.handle.net/2158/1276840.
Повний текст джерела"Reduced Order Modeling with Variable Spatial Fidelity for the Linear and Nonlinear Dynamics of Multi-Bay Structures." Doctoral diss., 2017. http://hdl.handle.net/2286/R.I.42064.
Повний текст джерелаDissertation/Thesis
Doctoral Dissertation Mechanical Engineering 2017