Tesis: "High-Fidelity simulations"

1

Cetraro, Giampaolo. "High-fidelity flow simulations of electroactive membrane wings". Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/416114/.

Texto completo

Resumen

This work is inspired by natural flyers such bats and insects. They show outstanding aerodynamic performance due to their flexible membrane wings and their ability to control its stiffness to improve manoeuvrability. In this work the fluid-structure coupling as well as the physics and the control of electroactive membranes have been simulated in a multiphysics framework. This study has allowed not only to have an insight of the flow mechanisms which allow a membrane wing to enhace lift and delay stall at high angles of attack but also lays the basis of the understanding of how an active control of the membrane’s stiffness in response to the unsteadiness of the fluid-structure coupling can deliver a more stable flight. In particular, numerical simulations are conducted for an electroactive membrane wing in a laminar incompressible flow. The fluid-structure interaction problem is simulated for electroactive polymers whose shape and stiffness can be modified by applying an electric potential. The Maxwell stresses generated by the electric field across the membrane produce an in-plane relaxation. Results from this work show that a fixed voltage applied to a prestretched membrane results in an increased camber and therefore enhanced mean lift. Moreover, the effect of a partial activation is considered as well as an oscillating voltage across the membrane. The results presented in this work indicate that the lift is increased at angles of attack up to a = 12 when the back section of the membrane is activated. In addition, lift is increased at higher angles of attack when the voltage oscillates at frequencies close to resonance of the coupled fluid-structure system. Finally, an active control has been simulated exploiting the electromechanical characteristics of electroactive polymers and using the membrane itself as a sensor. This work shows that when the whole surface of the membrane is used as sensor and actuator, a proportional integral control is able to reduce the membrane’s oscillations at medium angles of attack, delivering a more stable flight and smoother response to a gust.

Los estilos APA, Harvard, Vancouver, ISO, etc.

2

Garmann, Daniel J. "High-Fidelity Simulations of Transitional Flow Over Pitching Airfoils". University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1276955868.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

3

Talnikar, Chaitanya Anil. "Methods for design optimization using high fidelity turbulent flow simulations". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/106965.

Texto completo

Resumen

Thesis: S.M., Massachusetts Institute of Technology, School of Engineering, Center for Computational Engineering, Computation for Design and Optimization Program, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 75-79).
Design optimization with high-fidelity turbulent flow simulations can be challenging due to noisy and expensive objective function evaluations. The noise decays slowly as computation cost increases, therefore is significant in most simulations. It is often unpredictable due to chaotic dynamics of turbulence, in that it can be totally different for almost identical simulations. This thesis presents a modified parallel Bayesian optimization algorithm designed for performing optimization with high-fidelity simulations. It strives to find the optimum in a minimum number of evaluations by judiciously exploring the design space. Additionally, to potentially augment the optimization algorithm with the availability of a gradient, a massively parallel discrete unsteady adjoint solver for the compressible Navier-Stokes equations is derived and implemented. Both the methods are demonstrated on a large scale transonic fluid flow problem in a turbomachinery component.
by Chaitanya Anil Talnikar.
S.M.

Los estilos APA, Harvard, Vancouver, ISO, etc.

4

Mohan, Arvind Thanam. "Data-Driven Analysis Methodologies for Unsteady Aerodynamics from High Fidelity Simulations". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1512058039822368.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

5

Major, Maximillian R. "High-fidelity simulations of transverse electric waves propagating through Alcator C-Mod". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112469.

Texto completo

Resumen

Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (page 28).
This project represents an attempt to model the propagation of microwaves into Alcator C-Mod's plasma in high fidelity and with a reduced number of degrees of freedom. The success of this endeavor would accelerate progress within the field of fusion energy, as simulations of C-Mod's plasmas, or other plasmas in general, can be run more quickly while still maintaining their accuracy. The main procedure involves producing simulations within COMSOL that use mode numbers based on a power spectrum of waves at 4.6 GHz. These simulations are then overlaid to model how the waves will propagate as a function of position, plasma density, and local flux. Future work could focus on verifying the accuracy of the simulations when compared to data acquired from C-Mod as well as ensuring the run-time of the simulations is indeed faster than other methods.
by Maximillian R. Major.
S.B.

Los estilos APA, Harvard, Vancouver, ISO, etc.

6

Dhruv, Akash. "A Multiphase Solver for High-Fidelity Phase-Change Simulations over Complex Geometries". Thesis, The George Washington University, 2021. http://pqdtopen.proquest.com/#viewpdf?dispub=28256871.

Texto completo

Resumen

Complex interactions between solid, liquid and gas occur in many practical engineering applications, and are often difficult to quantify experimentally. A few examples include boiling over solid heaters, solidification melt-dynamics in metal casting, and convective cooling of electronic components. With the availability of scalable computational tools, high-fidelity simulations can provide new insight into these phenomena and answer open questions. In the present work, a multiphase solver is presented which can simulate problems involving phase transition over complex geometries. The dynamics of liquid-gas interface are modeled using a level-set technique, which utilizes Ghost Fluid Method (GFM) to account for sharp jump in pressure, velocity, and temperature across the multiphase boundary. The fluid-solid interactions are modeled using an Immersed Boundary Method (IBM) which uses a Moving Least Squared (MLS) reconstruction to calculate fluid-flow around the solid, along with an additional GFM forcing to model its effect on pressure, temperature and Conjugate Heat Transfer (CHT). The resulting three dimensional solver is fully explicit in time and uses a fractional step method for Navier-Stokes, energy, and mass transfer equations. Validation and verification cases are presented to demonstrate the accuracy of the solver in comparison to experimental and analytical problems, and results of high fidelity pool boiling simulations in varying gravity environments are discussed in detail.

Los estilos APA, Harvard, Vancouver, ISO, etc.

7

Zhu, Yixuan. "High fidelity simulations of optical waveguides for optical frequency conversion and frequency combs". Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/30946/.

Texto completo

Resumen

Conventional silicon-based electronics have developed dramatically in recent years; however, their optimum integration level is reaching its limits. To meet the requirements of dealing with this explosion of data, opto-electronic integrated circuits have provided a way out. Optical waveguides are crucial components which can be applied in opto-electronic integrated circuits to achieve specific functionalities, such as frequency conversion and frequency combs. Frequency conversion offers the possibility of converting the frequency components generated by lasers to a previously inaccessible frequency region in order to extend the application fields, such as gas sensing and optical communications. A frequency comb is a series of equally spaced frequency components, which could be utilized for frequency standards and optical clocks. This thesis has simulated frequency mixing processes, including second-harmonic generation and four-wave mixing in the optical waveguides based on second- and third-order nonlinearities in order to realize frequency conversion and generation of frequency combs. The focus of this thesis are silicon-based and AlGaAs waveguides because of their particular material characteristics. Silicon is the base of electronic devices so that silicon-based waveguides are complementary metal-oxide-semiconductor compatible and can be integrated with other electronic elements on a single chip. AlGaAs is a direct-band gap semi-conductor and has a small two-photon-absorption co-efficient. Both silicon and AlGaAs have a high refractive index and ensure the confinement of modes in waveguides. In addition, both have strong nonlinearity, leading to efficient nonlinear interactions and significant frequency mixing processes. This method of simulation was based on the finite-difference time-domain algorithm, incorporating linear dispersion and nonlinearity. Material dispersion was described as Lorentz medium and incorporated through Sellmeier equations. Geometric dispersion was taken into account in mode solver, which was applied in order to produce the fundamental modes for excitation sources. Second- and third-order nonlinearities (including Kerr-nonlinearity and Raman scattering) were incorporated with a piecewise linear recursive convolution method, which was solved by the Newton-Raphson method. In addition, a perfectly matched layer absorbing boundary condition and circular boundary condition were designed in the simulations. Programs were written in Fortran 95 and parallel computation was applied to improve the efficiency. This thesis has simulated four-wave mixing of five optical waveguides: GaAs suspended waveguide, deep-etched multi-layer Al_0.25 Ga_0.75 As waveguide, Al_0.3 Ga_0.7 As-on-insulator waveguide, silicon-on-insulator waveguide and silicon nitride-on-insulator waveguide. Phase matching conditions and phase mismatch factors were discussed for these waveguides. The results of four-wave mixing were observed when the phase matching conditions were satisfied. In deep-etched multi-layer Al_0.25 Ga_0.75 As waveguide, Raman scattering was incorporated and the results of simulation showed a good match with experimental data. This thesis has also simulated second-harmonic generation of highly birefringent AlGaAs waveguide. Type-I phase matching condition was achieved so that efficient second-harmonic generation was obtained.

Los estilos APA, Harvard, Vancouver, ISO, etc.

8

Carroll, Joseph Ray. "Time-averaged surrogate modeling for small scale propellers based on high-fidelity CFD simulations". Thesis, Mississippi State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3603422.

Texto completo

Resumen

Many Small Unmanned Aerial Vehicles (SUAV) are driven by small scale, fixed blade propellers. The flow produced by the propeller, known as the propeller slipstream, can have significant impact on SUAV aerodynamics. In the design and analysis process for SUAVs, numerous Computational Fluid Dynamic (CFD) simulations of the coupled aircraft and propeller are often conducted which require a time-averaged, steady-state approximation of the propeller for computational efficiency. Most steady-state propeller models apply an actuator disk of momentum sources to model the thrust and swirl imparted to the flow field by a propeller. These momentum source models are based on simplified theories which lack accuracy. Currently, the most common momentum source models are based on blade element theory. Blade element theory discretizes the propeller blade into airfoil sections and assumes them to behave as two-dimensional (2D) airfoils. Blade element theory neglects many 3D flow effects that can greatly affect propeller performance limiting its accuracy and range of application.

The research work in this dissertation uses a surrogate modeling method to develop a more accurate momentum source propeller model. Surrogate models for the time averaged thrust and swirl produced by each blade element are trained from a database of time-accurate, high-fidelity 3D CFD propeller simulations. Since the surrogate models are trained from these high-fidelity CFD simulations, various 3D effects on propellers are inherently accounted for such as tip loss, hub loss, post stall effect, and element interaction. These efficient polynomial response surface surrogate models are functions of local flow properties at the blade elements and are embedded into 3D CFD simulations as locally adaptive momentum source terms. Results of the radial distribution of thrust and swirl for the steady-state surrogate propeller model are compared to that of time-dependent, high-fidelity 3D CFD propeller simulations for various aircraft-propeller coupled situations. This surrogate propeller model which is dependent on local flow field properties simulates the time-averaged flow field produced by the propeller at a momentum source term level of detail. Due to the nature of the training cases, it also captures the accuracy of time dependent 3D CFD propeller simulations but at a much lower cost.

Los estilos APA, Harvard, Vancouver, ISO, etc.

9

Hedlund, Erik. "High-fidelity 3D acoustic simulations of wind turbines with irregular terrain and different atmospheric profiles". Thesis, Uppsala universitet, Avdelningen för beräkningsvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-298754.

Texto completo

Resumen

We study noise from wind turbines while taking irregular terrain and non-constant atmosphere into consideration. We will show that simulating the distribution of 3D acoustic waves can be done by using only low frequencies, thus reducing the computational complexity significantly.

Los estilos APA, Harvard, Vancouver, ISO, etc.

10

Christen, Henry Tiffany. "Community college educators' perceptions of the instructional infrastructure needed for high-fidelity paramedic training simulations". [Pensacola, Fla.] : University of West Florida, 2009. http://purl.fcla.edu/fcla/etd/WFE0000150.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

11

Merlini, Adrien. "Unified computational frameworks bridging low to high frequency simulations : fast and high fidelity modelling from brain to radio-frequency scenarios". Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2019. http://www.theses.fr/2019IMTA0130/document.

Texto completo

Resumen

Dans le domaine de l’électromagnétisme computationnel, les équations intégrales de frontière sont très largement utilisées pour résoudre certains des plus grands problèmes directs, grâce à leur grande efficacité. Cependant les équations intégrales du champ électrique et du champ combiné (EFIE et CFIE), deux des formulations les plus employées, souffrent d’instabilités à basse fréquence et à haute discrétisation, ce qui limite leur versatilité. Dans cette thèse différentes approches sont présentées pour obtenir des algorithmes applicables aussi bien à des problèmes de compatibilité électromagnétique qu’à des applications radar. Les solutions présentées incluent (i) l’extension des projecteurs dit quasi-Helmholtz (qH) aux modélisations d’ordre supérieur ; (ii) l’utilisation de ces projecteurs pour stabiliser l’équation intégrale du champ magnétique et former une CFIE extrêmement précise, augmentée par des techniques de type Calderón, qui ne souffre de problèmes ni à basse fréquence ni à haute discrétisation et qui n’est pas sujette aux résonances artificielles ; (iii) le développement d’une EFIE filaire, basée sur des B-splines linéaires et les projecteurs qH, stable aux deux extrémités du spectre. Ces travaux ont été suivis de l’ouverture d’un nouvel axe de recherche visant l’amélioration des techniques de résolution des problèmes inverses en électromagnétique, avec pour objectif principal l’augmentation des performances des interfaces cerveau machine (BCIs). Les premiers résultats obtenus incluent le développement de l’un des premiers systèmes libres de simulation de bout en bout de session de BCI ayant été publié après revue par les pairs
In computational electromagnetics, boundary integral equations are the scheme of choice for solving extremely large forward electromagnetic problems due to their high efficiency. However, two of the most used of these formulations, the electric and combined field integral equations (EFIE and CFIE), suffer from stability issues at low frequency and dense discretization, limiting their applicability at both ends of the spectrum. This thesis focusses on remedying these issues to obtain full-wave solvers stable from low to high frequencies, capable of handling scenarios ranging from electromagnetic compatibility to radar applications. The solutions presented include (i) extending the quasi-Helmholtz (qH) projectors to higher order modeling thus combining stability with high order convergence rates; (ii) leveraging on the qH projectors to numerically stabilize the magnetic field integral equation and obtain a highly accurate and provably resonance-free Calderón-augmented CFIE immune to both of the aforementioned problems; and(iii) introducing a new low frequency and dense discretization stable wire EFIE based on projectors and linear B-splines. In addition, a research axis focused on enhancing Brain Computer Interface (BCIs) with high resolution electromagnetic modeling of the brain has been opened ; a particular attention is dedicated to the inverse problem of electromagnetics and the associated integral equation-based forward problem. The first results of this new line of investigations include the development of one of the first peer-reviewed, freely available framework for end-to-end simulation of BCI experiments

Los estilos APA, Harvard, Vancouver, ISO, etc.

12

Bowles, Ronald Robin. "From diagnosis to discernment : fostering the development of clinical judgment of paramedic learners in immersive high fidelity simulations". Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44556.

Texto completo

Resumen

Paramedic educators are challenged to produce greater numbers of graduates who are better prepared to function in an evolving health care system. The growth of high fidelity simulation (HFS) holds promise for reducing reliance on the practicum environment, long a crucial step between the classroom and field practice. Yet, despite significant investment in simulation infrastructure, HFS is still seen as an adjunct to, but not a replacement for, practicum placement. The practical problem addressed in this study, then, was the presumption that HF simulation can reduce reliance on practicum placement. The research question explored how HFS influences the development of clinical competence and clinical judgment. This multiple-case study employed a multi-vocal approach, gathering data from 75 classroom and HF simulations. An iterative, inductive process of analysis provided a phenomenological exploration of participants’ experiences and interactions and a critical analysis of their judgments and decision making. The findings in this study suggest that existing paramedic simulations and the practicum represent radically different learning environments, each with its own sets of roles, expectations, patterns of practice, and methods of evaluation that call on different epistemological and ontological conceptions of what constitutes competent practice, what knowledge matters most, and how learning occurs. The varied learning activities in this study fostered different ways of knowing as learners moved from the consistency of context-independent skill performance to the socially constructed adaptation of procedures and protocols in dynamic simulations, and, finally, to the socially negotiated understandings arising from co-emergent activity in a field setting. Effective simulations require situational blends of fidelity to create environments realistic enough to meet their pedagogic goals. Simulations intended to foster clinical competence and clinical judgment must provide occasions for discernment; they must create a milieu involving complex interpersonal interactions and genuine opportunities for clinical decision making. Thus, paramedic simulations must be as concerned with role, environmental, interpersonal, and social/cultural fidelity as with physiological and procedural fidelity. In this sense, populating HFS more richly with actors and authentic interdisciplinary responders may often be as important as the use of HF mannequins and standardized patients.

Los estilos APA, Harvard, Vancouver, ISO, etc.

13

D'Alessio, Giuseppe. "Data-driven models for reacting flows simulations: reduced-order modelling, chemistry acceleration and analysis of high-fidelity data". Doctoral thesis, Universite Libre de Bruxelles, 2021. https://dipot.ulb.ac.be/dspace/bitstream/2013/328064/5/contratGA.pdf.

Texto completo

Resumen

Combustion science must necessarily go through a deep process of innovation, as only improving the energy efficiency and the fuel flexibility it will be possible to mitigate the impact of the anthropogenic activities on the climate and the environment. Because of the strong relation that is observed in chemically reacting flows between the fluid-dynamic conditions and the chemical kinetics, the use of Computational Fluid Dynamics (CFD) simulations with detailed kinetic mechanisms represents the best tool to optimize and develop novel combustion systems. In fact, while the CFD provides for the possibility to retrieve information that cannot be extracted by using experimental means (such as the turbulence-chemistry interaction and the local straining rates) and it avoids the costs associated to the scale-up process from laboratory scale experiments, the use of detailed kinetic mechanisms offers the possibility to correctly describe process conditions which are relevant from an industrial point of view (i.e. in which the chemical and mixing time scales are comparable), as well as to predict the formation of complex chemical species, such as the pollutants. Nevertheless, the use of detailed kinetic mechanisms in numerical simulations adds a considerable number of differential equations to be solved (because of the large number of species which are taken into account), and therefore increases the computational complexity of the CFD model. Thus, Machine Learning (ML) algorithms and Reduced-Order Models (ROMs) can be effectively included in the numerical description of chemically reacting flows. In fact, they can be used either to reduce the computational cost associated to the large number of equations in CFD simulations carried out with detailed chemistry, or to leverage the detailed information which can be found in massive, high-fidelity, data obtained from Direct Numerical Simulations (DNS), for model development and validation. In this Thesis, unsupervised and supervised learning algorithms were employed to design a novel adaptive-chemistry approach: the Sample-Partitioning Adaptive Reduced Chemistry (SPARC). This framework can be used to reduce the computational effort required by detailed CFD simulations thanks to a kinetic reduction accomplished in light of the local conditions of the thermochemical field. Several machine-learning algorithms, such as the Principal Component Analysis (PCA), the Local Principal Component Analysis (LPCA), and Artificial Neural Networks (ANNs) were coupled with the Direct Relation Graph with Error Propagation (DRGEP), a graph-based tool for the automatic reduction of kinetic mechanisms. The aforementioned algorithms were compared to achieve the optimal formulation of the adaptive approach, such that the best performances, in terms of accuracy and computational speed-up with respect to the CFD simulation carried out with detailed kinetics, could be obtained. Finally, PCA-based algorithms were proposed and tested to perform feature extraction and local feature selection from high-fidelity data, which were obtained by means of a DNS of a n-heptane jet reacting in air. The PCA, as well as two formulations of LPCA, and the Procrustes analysis were employed and compared with the aim to extract the main features of the turbulent reacting jet in an unsupervised fashion (i.e. to perform data mining tasks), as well as to aid the formulation of local optimized ROMs. All the codes employed to perform the unsupervised and supervised machine learning tasks in the current work were also included in an open-source Python framework, called OpenMORe, designed to perform reduction, clustering and data analysis, and specifically conceived for reacting flows. In fact, although many open-source Python software are already available, they often cannot be adapted to the user’s specific needs, unlike OpenMORe. In addition, many features such as the PCA-based clustering algorithm, or the local feature selection via PCA, are not yet available on any commercial or open-source software, to the best of the author’s knowledge.
Doctorat en Sciences de l'ingénieur et technologie
This thesis is submitted to the Université Libre de Bruxelles (ULB) and to the Politecnico di Milano for the degree of philosophy doctor. This doctoral work has been performed at the Université Libre de Bruxelles, École polytechnique de Bruxelles, Aero-Thermo-Mechanics Laboratory, Bruxelles, Belgium with Professor Alessandro Parente and at the Politecnico di Milano, CRECK Modelling Lab, Department of Chemistry, Materials and Chemical Engineering, Milan, Italy with Professor Alberto Cuoci.
info:eu-repo/semantics/nonPublished

Los estilos APA, Harvard, Vancouver, ISO, etc.

14

Parthasarathy, Nikhil Kaushik. "An efficient algorithm for blade loss simulations applied to a high-order rotor dynamics problem". Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/189.

Texto completo

Resumen

In this thesis, a novel approach is presented for blade loss simulation of an aircraft gas turbine rotor mounted on rolling element bearings with squeeze film dampers, seal rub and enclosed in a flexible housing. The modal truncation augmentation (MTA) method provides an efficient tool for modeling this large order system with localized nonlinearities in the ball bearings. The gas turbine engine, which is composed of the power turbine and gas generator rotors, is modeled with 38 lumped masses. A nonlinear angular contact bearing model is employed, which has ball and race degrees of freedom and uses a modified Hertzian contact force between the races and balls and for the seal rub. This combines a dry contact force and viscous damping force. A flexible housing with seal rub is also included whose modal description is imported from ANSYS. Prediction of the maximum contact load and the corresponding stress on an elliptical contact area between the races and balls is made during the blade loss simulations. A finite-element based squeeze film damper (SFD), which determines the pressure profile of the oil film and calculates damper forces for any type of whirl orbit is utilized in the simulation. The new approach is shown to provide efficient and accurate predictions of whirl amplitudes, maximum contact load and stress in the bearings, transmissibility, thermal growths, maximum and minimum damper pressures and the amount of unbalanced force for incipient oil film cavitation. It requires about 4 times less computational time than the traditional approaches and has an error of less than 5 %.

Los estilos APA, Harvard, Vancouver, ISO, etc.

15

Novikov, Yaroslav. "Development Of A High-fidelity Transient Aerothermal Model For A Helicopter Turboshaft Engine For Inlet Distortion And Engine Deterioration Simulations". Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614389/index.pdf.

Texto completo

Resumen

Presented in this thesis is the development of a high-fidelity aerothermal model for GE T700 turboshaft engine. The model was constructed using thermodynamic relations governing change of flow properties across engine components, and by applying real component maps for the compressor and turbines as well as empirical relations for specific heats. Included in the model were bleed flows, turbine cooling and heat sink effects. Transient dynamics were modeled using inter-component volumes method in which mass imbalance between two engine components was used to calculate the inter-component pressure. This method allowed fast, high-accuracy and iteration-free calculation of engine states. Developed simulation model was successfully validated against previously published simulation results, and was applied in the simulation of inlet distortion and engine deterioration. Former included simulation of steady state and transient hot gas ingestion as well as transient decrease in the inlet total pressure. Engine deterioration simulations were performed for four different cases of component deterioration with parameters defining engine degradation taken from the literature. Real time capability of the model was achieved by applying time scaling of plenum volumes which allowed for larger simulation time steps at very little cost of numerical accuracy. Finally, T700 model was used to develop a generic model by replacing empirical relations for specific heats with temperature and FAR dependent curve fits, and scaling T700 turbine maps. Developed generic aerothermal model was applied to simulate steady state performance of the Lycoming T53 turboshaft engine.

Los estilos APA, Harvard, Vancouver, ISO, etc.

16

Laurent, Charlelie. "Low-order modeling and high-fidelity simulations for the prediction of combustion instabilities in liquid rocket engines and gas turbines". Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0038.

Texto completo

Resumen

Au cours des dernières décennies, les instabilités de combustion ont constitué un important défi pour de nombreux projets industriels, en particulier dans la conception de moteurs-fusées à ergols liquide et de turbines à gaz. L'atténuation de leurs effets nécessite une solide compréhension scientifique de l'interaction complexe entre la dynamique de flamme et les ondes acoustiques qu'elles impliquent. Au cours de cette thèse, plusieurs directions ont été explorées pour fournir une meilleure compréhension de la dynamique des flammes dans les moteurs-fusées cryogéniques, ainsi que des méthodes numériques plus efficaces et robustes pour la prédiction des instabilités thermoacoustiques dans les chambres de combustion à géométries complexes. La première facette de ce travail a consisté en la résolution de modes thermoacoustiques dans les chambres de combustion complexes comportant à injecteurs multiples, une tâche qui nécessite souvent des simplifications pour être abordable en termes de coût de calcul. Ces hypothèses physiques nécessaires ont conduit à la popularité croissante des modèles bas-ordre acoustiques, parmi lesquels ceux utilisant l'expansion de Galerkin ont démontré une efficacité prometteuse tout en conservant une précision satisfaisante. Ceux-ci sont cependant limités à des géométries simples qui n'intègrent pas les caractéristiques complexes des systèmes industriels. Une grande partie de ce travail a donc consisté tout d'abord à identifier clairement les limitations mathématiques de l'expansion classique de Galerkin, puis à concevoir un nouveau type d'expansion modale, appelé expansion sur frame, qui ne souffre pas des mêmes restrictions. En particulier, l'expansion sur frame est capable de représenter avec précision le champ de vitesse acoustique près des parois de la chambre de combustion autres que des murs rigides, une capacité cruciale qui manque à la méthode Galerkin. Dans ce travail, le concept d'expansion modale de surface a également été introduit pour modéliser des frontières topologiquement complexes, comme les plaques multi-perforées rencontrées dans les turbines à gaz. Ces nouvelles méthodes numériques ont été combinées avec le formalisme state-space pour construire des réseaux acoustiques de systèmes complexes. Le modèle obtenu a été implémenté dans le code STORM (State-space Thermoacoustic low-ORder Model), qui permet la modélisation bas-ordre des instabilités thermoacoustiques dans des géométries arbitrairement complexes. Le deuxième ingrédient de la prédiction des instabilités thermoacoustiques est la modélisation de la dynamique de flamme. Ce travail a traité de ce point, dans le cas spécifique d'une flamme-jet cryogénique caractéristique d'un moteur-fusée à ergols liquides. Les phénomènes contrôlant la dynamique de flamme ont été identifiés grâce à des Simulations aux Grandes Échelles (SGE) du banc d'essai expérimental Mascotte, où les deux réactifs (CH4 et O2) sont injectés dans des conditions transcritiques. Une première simulation donne un aperçu détaillé de la dynamique intrinsèque de la flamme. Plusieurs SGE avec modulation harmonique de l'injection de carburant, à différentes fréquences et amplitudes, ont été effectués afin d'évaluer la réponse de la flamme aux oscillations acoustiques et de calculer une Fonction de Transfert de Flamme (FTF). La réponse non-linéaire de la flamme, notamment les interactions entre les oscillations intrinsèques et forcées, a également été étudiée. Enfin, la stabilisation de cette flamme dans la région proche de l'injecteur, qui est d'une importance primordiale sur la dynamique globale de la flamme, a été étudiée grâce à une simulation directe multi-physique, où un problème couplé de transfert de chaleur est résolu au niveau de la lèvre de l'injecteur
Over the last decades, combustion instabilities have been a major concern for a number of industrial projects, especially in the design of Liquid Rocket Engines (LREs) and gas turbines. Mitigating their effects requires a solid scientific understanding of the intricate interplay between flame dynamics and acoustic waves that they involve. During this PhD work, several directions were explored to provide a better comprehension of flame dynamics in cryogenic rocket engines, as well as more efficient and robust numerical methods for the prediction of thermoacoustic instabilities in complex combustors. The first facet of this work consisted in the resolution of unstable thermoacoustic modes in complex multi-injectors combustors, a task that often requires a number of simplifications to be computationally affordable. These necessary physics-based assumptions led to the growing popularity of acoustic Low-Order Models (LOMs), among which Galerkin expansion LOMs have displayed a promising efficiency while retaining a satisfactory accuracy. Those are however limited to simple geometries that do not incorporate the complex features of industrial systems. A major part of this work therefore consisted first in clearly identifying the mathematical limitations of the classical Galerkin expansion, and then in designing a novel type of modal expansion, named a frame expansion, that does not suffer from the same restrictions. In particular, the frame expansion is able to accurately represent the acoustic velocity field, near non-rigid-wall boundaries of the combustor, a crucial ability that the Galerkin method lacks. In this work, the concept of surface modal expansion is also introduced to model topologically complex boundaries, such as multi-perforated liners encountered in gas turbines. These novel numerical methods were combined with the state-space formalism to build acoustic networks of complex systems. The resulting LOM framework was implemented in the code STORM (State-space Thermoacoustic low-ORder Model), which enables the low-order modeling of thermoacoustic instabilities in arbitrarily complex geometries. The second ingredient in the prediction of thermoacoustic instabilities is the flame dynamics modeling. This work dealt with this problem, in the specific case of a cryogenic coaxial jet-flame characteristic of a LRE. Flame dynamics driving phenomena were identified thanks to three-dimensional Large Eddy Simulations (LES) of the Mascotte experimental test rig where both reactants (CH4 and O2) are injected in transcritical conditions. A first simulation provides a detailed insight into the flame intrinsic dynamics. Several LES with harmonic modulation of the fuel inflow at various frequencies and amplitudes were performed in order to evaluate the flame response to acoustic oscillations and compute a Flame Transfer Function (FTF). The flame nonlinear response, including interactions between intrinsic and forced oscillations, were also investigated. Finally, the stabilization of this flame in the near-injector region, which is of primary importance on the overall flame dynamics, was investigated thanks to muulti-physics two-dimensional Direct Numerical Simulations (DNS), where a conjugate heat transfer problem is resolved at the injector lip

Los estilos APA, Harvard, Vancouver, ISO, etc.

17

Chen, Yung-Yu. "A Multi-Physics Software Framework on Hybrid Parallel Computing for High-Fidelity Solutions of Conservation Laws". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1313000975.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

18

Paskin, Liad. "On the interaction of fast traveling Ocean Waves and the Atmospheric Boundary Layer : A Mechanistic Approach combining Field Measurements and High-fidelity Simulations". Thesis, Ecole centrale de Nantes, 2022. http://www.theses.fr/2022ECDN0012.

Texto completo

Resumen

Dans les zones côtières, l’industrie de l’énergie éolienne migre vers l’environnement marin, où de vastes espaces sont encore disponibles avec des conditions de vent plus fort et mieux contrôlé. L’environnement marin impose de nouveaux défis à une industrie éolienne pourtant bien établie. Il est impératif de prédire et de décrire avec précision la ressource éolienne en mer afin de concevoir des solutions techniques rentables. L’écoulement concerné est caractérisé par une couche limite atmosphérique (CLA), turbulente, où la dynamique de l’océan modifie considérablement l’écoulement atmosphérique par une capacité thermique plus élevée, et par des interactions vent-vagues complexes, importantes dans des situations assez courantes. Cette thèse passe en revue et étend les connaissances actuelles concernant les interactions vent-vagues dans la partie inférieure de la CLA Marine (CLAM), où elles peuvent être importantespour la caractérisation de la ressource éolienne. La CLAM est étudiée par des expériences physiques et numériques, afin de révéler le rôle des mouvements Induits par les Vagues (IV) transférés de la mer vers l’atmosphère. Grâce à l’utilisation d’expériences physiques et numériques complémentaires, de nouvelles perspectives sur les processus d’interaction vent-vague sont obtenues
In coastal areas, the wind energy industry migrates to the offshore environment, where huge spaces are still available in stronger and better behaved wind conditions. The offshore environment imposes new challenges to a well established wind energy industry. It is imperative to accurately predict and describe the offshore wind resource in order to design cost efficient solutions. The concerned flow is characterized by a turbulent Atmospheric Boundary Layer (ABL) where the ocean’s dynamics significantly alter the atmospheric flow through higher heat capacity and complex wind-wave interactions important in fairly common situations.So this Thesis reviews and extends the current knowledge regarding Wind-Wave interactions in the lower part of the Marine ABL (MABL), where they are possibly significant in the characterization of the wind resource. The MABL is investigated through physical and numerical experiments, to reveal the role of Wave Induced (WI) motions transferred from the sea into the atmosphere. Thanks to the use of complementary physical and numerical experiments, new insights on the wind-wave interaction processes are obtained

Los estilos APA, Harvard, Vancouver, ISO, etc.

19

Rönnberg, Kristian. "Heat-transfer simulations applied to electrical machines". Licentiate thesis, KTH, Teknisk mekanik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-286686.

Texto completo

Resumen

Electrification and energy efficiency are two important aspects in present scenarios describing a sustainable future. Electric motors constitute a large fractionof industry’s electricity demand today, and it is expected to remain high inthe future. Electrification of the transport sector is expected in a sustainabledevelopment scenario, leading to a large increase in electric vehicles. Theirpropulsion systems will contain one or several motors.Development of new energy efficient motors and generators requires highresolution methods for studying and describing heat transfer phenomena. Thissince temperature level affects a motors efficiency and effective and efficientcooling allows for using less active material in the motor.In this work simulations of temperature distribution in a motor for tractionapplications are performed with different specifications of the loss distributionand distribution of coolant flow. Simulation results are compared to measuredvalues. The comparison shows how the simulation results differ in comparisonto the measurements. It can be concluded that attention needs to be paid tohow the simulation is defined when comparing to measured data.In establishing high resolution simulation approaches, the heat transfersystem constituting of an impinging jet on a flat plate is considered as aprototype problem. A Large-Eddy Simulation (LES) approach is employed tostudy the heat transfer and gather heat transfer data. Statistical analysis ofsampled heat transfer data shows behavior which is previously unpublished.The application of Proper Orthogonal Decomposition (POD), on the heattransfer field, and Extended Proper Orthogonal Decomposition (EPOD), linkingheat transfer modes with fluid flow modes, regarding the impinging jet systemis performed for the first time. The results show a clear correlation betweenstructures in the heat transfer field and structures in the fluid flow field.The investigated simulation methods and approaches can be employed instudies of heat transfer in electric machines.

Los estilos APA, Harvard, Vancouver, ISO, etc.

20

Bienner, Aurélien. "Real-gas effects on freestream induced transition and losses in ORC turbine flows". Electronic Thesis or Diss., Paris, HESAM, 2024. http://www.theses.fr/2024HESAE016.

Texto completo

Resumen

Les cycles de Rankine organique (ORC) apparaissent comme l'une des solutions pour répondre aux défis énergétiques et environnementaux actuels, en raison de leur important potentiel énergétique. L'un des composants clés des ORC est le détendeur, généralement une turbine. Pour les petits systèmes, cette dernière fonctionne dans les régimes transsoniques à supersoniques et peut être influencée par les propriétés de la vapeur organique utilisée, présentant ainsi des effets non idéaux. Dans cette étude, nous examinons les transitions de couche limite (CL) et le mécanisme des pertes au sein des turbines dans des conditions représentatives des ORC pour le fluide Novec649. Nous débutons par la présentation des premières simulations numériques directes (DNS) et des simulations à grandes échelles (LES) de CL transitionnant et turbulentes de Novec dans des conditions subsoniques élevées. Dans l'état turbulent, les profils des propriétés dynamiques de l'écoulement sont peu affectés par les propriétés du gaz et demeurent très proches de la DNS incompressible, malgré la vitesse élevée de l'écoulement subsonique, même si de véritables mais très faibles effets de compressibilité sont présents. Notre stratégie LES est validée par rapport à la DNS et est utilisée pour étudier l'influence de la fréquence et de l'amplitude du forçage sur l'état turbulent établi. Ensuite, pour la première fois, nous étudions, par LES, la transition induite par la turbulence extérieure (FST) de CL de gaz dense sur des plaques planes et autour du bord d'attaque d'une turbine. En raison du nombre de Reynolds élevé, les fines CL interagissent avec de larges structures turbulentes qui peuvent, pour des intensités relativement élevées, favoriser un mécanisme de transition non linéaire au lieu du mécanisme classique de transition par stries laminaires. Comparées au Novec, les CL d'air se révèlent légèrement plus instables mais conservent globalement des caractéristiques similaires, notamment en ce qui concerne les mécanismes de transition observés. Enfin, l'écoulement autour d'une configuration idéalisée d'aube est abordé au moyen de simulations DDES (Delayed Detached-Eddy Simulations), permettant une analyse fine des phénomènes instationnaires. À mesure que la non-idéalité de l'écoulement augmente, le rapport de pression diminue et les pertes augmentent. Comparativement à l'air, la capacité thermique élevée du Novec réduit les fluctuations de température, éliminant ainsi le phénomène dit de séparation d'énergie, tout en accentuant les fluctuations de pression dans le sillage. En comparaison avec les DDES, les simulations RANS conduisent à une sous-estimation des pertes d'environ 20%
Organic Rankine Cycle (ORC) systems appear as one of the solutions to answer the current energy and environmental challenges, owing to their significant potential for generating power. A key component for ORC is the expander, most often a turbine. For small systems, the latter works in the transonic to supersonic regimes and can be affected by the properties of the organic vapor used and exhibit strong non-ideal effects. In the present study, we investigate boundary layer (BL) transitions and losses mechanism in turbines under conditions representative of ORC for the organic vapor Novec649. We begin by reporting the first direct numerical simulation (DNS) and large-eddy simulations (LES) of transitional and turbulent BL of Novec at high-subsonic conditions. In the turbulent state, the profiles of dynamic flow properties are little affected by the gas properties and remain very close to incompressible DNS, despite the high-subsonic flow speed and even if genuine but very small compressibility effects are present. Our LES strategy is validated against the reference DNS and is used to investigate the influence of forcing frequency and amplitude on the established turbulent state. Then, for the first time, we investigate freestream turbulence (FST)-induced transition of dense-gas BL on flat plates and around the leading-edge of a turbine by means of LES. Due to the high Reynolds number conditions, the thin BL experience large-scale incoming turbulent structures which can, for relatively high intensities, promote a non-linear transition mechanism instead of the classical laminar streak transition mechanism. Compared to Novec flows, air BL are found to be slightly more unstable but retains overall similar characteristics, in particular concerning the transition mechanisms observed. Finally, the flow around an idealized blade vane configuration is tackle by means of Delayed Detached-Eddy Simulations (DDES), allowing fine-detail analysis of unsteady flow phenomena. As the non-ideality of the flow increases, a lower pressure ratio is achieved and the losses increases. With regards to air, Novec's high heat capacity reduces temperature fluctuations, suppressing the so-called energy separation phenomena, while accentuating pressure fluctuations in the wake. Compared to DDES, RANS simulations leads to an underestimation of the losses by about 20%

Los estilos APA, Harvard, Vancouver, ISO, etc.

21

Nehring, Wendy M. y D. Dubose. "Integrating High-Fidelity Patient Simulation in Nursing Education". Digital Commons @ East Tennessee State University, 2009. https://dc.etsu.edu/etsu-works/6734.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

22

Zainali, Amir. "High-Fidelity Numerical Simulation of Shallow Water Waves". Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/73653.

Texto completo

Resumen

Tsunamis impose significant threat to human life and coastal infrastructure. The goal of my dissertation is to develop a robust, accurate, and computationally efficient numerical model for quantitative hazard assessment of tsunamis. The length scale of the physical domain of interest ranges from hundreds of kilometers, in the case of landslide-generated tsunamis, to thousands of kilometers, in the case of far-field tsunamis, while the water depth varies from couple of kilometers, in deep ocean, to few centimeters, in the vicinity of shoreline. The large multi-scale computational domain leads to challenging and expensive numerical simulations. I present and compare the numerical results for different important problems --- such as tsunami hazard mitigation due to presence of coastal vegetation, boulder dislodgement and displacement by long waves, and tsunamis generated by an asteroid impact --- in risk assessment of tsunamis. I employ depth-integrated shallow water equations and Serre-Green-Naghdi equations for solving the problems and compare them to available three-dimensional results obtained by mesh-free smoothed particle hydrodynamics and volume of fluid methods. My results suggest that depth-integrated equations, given the current hardware computational capacities and the large scales of the problems in hand, can produce results as accurate as three-dimensional schemes while being computationally more efficient by at least an order of a magnitude.
Ph. D.

Los estilos APA, Harvard, Vancouver, ISO, etc.

23

Seitz, Andrew C. "A high fidelity global positioning system receiver simulation". Ohio University / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1172865665.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

24

Paragas, Ma Zolaica. "Development of Evidence-Based Scenario with High Fidelity Simulation to Improve Nursing Care of Chest Pain Patients". ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/2098.

Texto completo

Resumen

Cardiovascular disease remains the leading cause of mortality in the United States, and a primary educational objective is to develop professional competency among nurses to ensure the provision of safe and effective care to the cardiac patient. Benner's theory of novice-to-expert led to the development of an evidence-based scenario for the care of the patient with chest pain using risk-free high-fidelity simulation environments that focused on assessment, history taking, and communication, while evaluating improvements in the competency of nurses providing care to chest pain patients. Thirty-six nurses volunteered in the study. Feedback from nurse educators, which led to modifications to the scenario, preceptor evaluation of participants during simulation, and post simulation feedback of participants, were analyzed using an inductive and exploratory theme analysis. Participants reported they learned meaningful information but felt somewhat confused regarding the correct course of action when multiple events occurred simultaneously. Preceptors' feedback identified participant failure to meet stated scenario expectations. Quantitative analysis of data, using one sample t test, compared the pre- and post-test scores measuring participant knowledge on assessment, history taking, and communication. Although knowledge scores increased, the difference was not clinically significant based on the negative feedback from both preceptor and participants. Accurate appraisal of nurses' competency in assessment, history-taking, and communication skills is needed prior to exposure to simulation. Simulation scenarios may be more clinically significant when tailored to an individual participant's competency levels.

Los estilos APA, Harvard, Vancouver, ISO, etc.

25

Kim, Hansoo. "Reference Model Based High Fidelity Simulation Modeling for Manufacturing Systems". Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5207.

Texto completo

Resumen

Today, discrete event simulation is the only reliable tool for detailed analysis of complex behaviors of modern manufacturing systems. However, building high fidelity simulation models is expensive. Hence, it is important to improve the simulation modeling productivity. In this research, we explore two approaches for the improvement of simulation modeling productivity. One approach is the Virtual Factory Approach, using a general-purpose model for a system to achieve various simulation objectives with a single high fidelity model through abstraction. The other approach is the Reference Model Approach, which is to build fundamental building blocks for simulation models of any system in a domain with formal descriptions and domain knowledge. In the Virtual Factory Approach, the challenge is to show the validity of the methodology. We develop a formal framework for the relationships between higher fidelity and lower fidelity models, and provide justification that the models abstracted from a higher fidelity model are interchangeable with various abstract simulation models for a target system. For the Reference Model Approach, we attempt to overcome the weak points inherited from ad-hoc modeling and develop a formal reference model and a model generation procedure for discrete part manufacturing systems, which covers most modern manufacturing systems.

Los estilos APA, Harvard, Vancouver, ISO, etc.

26

Kapadoukas, Georgios G. "High fidelity on and near the ground aircraft flight simulation". Thesis, University of Brighton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361583.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

27

Nehring, Wendy M., T. Wexler, F. Hughes y A. Greenwell. "“Faculty Forward:” Faculty Development in High-Fidelity Simulation in Nursing". Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etsu-works/6722.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

28

Saleta, Jennifer M. "The effects of utilizing high-fidelity simulation in medical residency programs". Thesis, St. John's University, School of Education and Human Services, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3537049.

Texto completo

Resumen

The purpose of this study was to examine the effects of utilizing high-fidelity simulation on the team performance, perceived level of learning, and satisfaction of resident physicians in a simulated cardiac resuscitation scenario. This study was significant because it filled a gap in the literature about how methods of education impact healthcare practitioners. While a body of research exists in education on adult learning principles, there are few studies on how applying adult learning principles to professional development is an effective method of instruction in healthcare.

A convenience sample of resident physicians from two hospitals that are part of a large health system was utilized for this study. Resident physicians participated in a simulated mock cardiac resuscitation scenario monthly. The Simulated Cardiac Resuscitation Team Performance Evaluation instrument was utilized to assess the team performance of the residents in the scenarios. A program evaluation form was administered to measure perceived level of learning and satisfaction with the simulation experience.

One-way multivariate analyses of variance were conducted to evaluate the relationships between year of residency and gender and the team performance score on the Simulated Cardiac Resuscitation Team Performance Evaluation. Significant differences were not found among the years of residency on the dependent measures. Significant differences were not found between the genders on the dependent measures. A one-way multivariate analysis of variance was conducted to evaluate the relationship between year of residency and the level of satisfaction and perceived level of learning of the resident physicians. Significant differences were not found among the three years of residency on the dependent measures. A one-way multivariate analysis of variance was conducted to evaluate the relationship between gender and the level of satisfaction and perceived level of learning of the resident physicians. Significant differences were not found between genders on the dependent measures. A one-way multivariate analysis of variance was conducted to evaluate the relationship between prior use of simulation and the level of satisfaction and perceived level of learning of the resident physicians. Significant differences were not found between prior use of simulation on the dependent measures.

Los estilos APA, Harvard, Vancouver, ISO, etc.

29

Garside, Mark James. "Nursing expertise and self-efficacy following high fidelity simulation-based training". Thesis, University of Newcastle upon Tyne, 2013. http://hdl.handle.net/10443/2157.

Texto completo

Resumen

The use of simulation in healthcare education has dramatically increased in popularity over the last two decades. It is thought to provide a standardised way of exposing learners to clinical situations where they can safely learn from mistakes. However, there is a lack of evidence to suggest whether simulation-based training offers significant benefits for clinical care over more traditional educational techniques, especially when the objective is a clinical judgement or diagnosis rather than a practical skill. This thesis explores whether the use of a high-fidelity patient simulator during training has an effect on the self-efficacy beliefs and clinical practice of learners, and whether this varies according to learners’ prior experience with simulation training or the clinical topic. Data were collected through semi-structured interviews with 16 qualified nurses, all of whom had attended a simulation-based training programme designed to improve clinical judgement skills. Analysis and data collection were iterative. Using a social constructionist epistemology, a thematic analysis approach was employed. High-fidelity simulation was perceived to be valuable by participants, who reported that it helped them to contextualize their knowledge and feel more confident about relevant clinical judgements. The reported impact on self-efficacy varied according to how much personal experience learners had in either the relevant clinical domain or with simulation as a training technique. However, greater belief in personal clinical judgement skills did not necessarily change reported clinical behaviour. The need for psychological fidelity during training appeared to be inversely related to clinical experience, reflecting the importance of contextual sensitivity in the planning of simulation-assisted training. Future research should examine whether these findings are reproducible in other settings, and consider whether simulation fidelity should be tailored to specific learner profiles.

Los estilos APA, Harvard, Vancouver, ISO, etc.

30

Merkle, Frank [Verfasser]. "High-fidelity Simulation in der Kardiotechnik – Evaluation einer Notfallcheckliste / Frank Merkle". Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2021. http://d-nb.info/1234983923/34.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

31

Letzgus, Johannes [Verfasser]. "High-Fidelity Simulation of Dynamic Stall on Helicopter Rotors / Johannes Letzgus". München : Verlag Dr. Hut, 2021. http://d-nb.info/1238423159/34.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

32

Baqar, S. "Low-cost PC-based high-fidelity infrared signature modelling and simulation". Thesis, Cranfield University, 2008. http://hdl.handle.net/1826/2912.

Texto completo

Resumen

In the light of the increasing terrorist SAMs threat to civil and military aircraft, the need of a high-fidelity, low-cost, IR signature scene modelling and simulation capability that could be used for development, testing and evaluation of IRCM systems cannot be overlooked. The performance evaluation, training and testing of IR missiles or other IR based weapon systems, is very expensive and is also dependent upon atmospheric factors. Whereas, the computer based non-destructive simulation can provide a cost-effective alternative to field trials. An effort has been made to model the IR scene signature using virtual reality modelling tools and integrating this model into the missile-target engagement and countermeasure simulator. The developed algorithm can simulate passive IR imaging seeker engagements with aerial targets. The presented algorithm uses the developed models for IR signature of the target, the background, the flare spectral and temporal responses and the flare ballistic trajectory. The missile guidance, auto-pilot and tracker algorithms have also been developed. The atmospheric conditions have been modelled, using LOWTRAN, as “good”, “typical” or “bad” to account for atmospheric transmittance and the sky-radiance. The results were analysed and validated through four test scenarios. The code is written in MATLAB which gives it openness for user verification/validation and also flexibility for any future modifications. The work presented may help the IRCM designer and pilots to evaluate potential strategies to defeat the imaging seeker threat.

Los estilos APA, Harvard, Vancouver, ISO, etc.

33

Selle, Andrew Paul. "Hybrid techniques for high-fidelity physical simulation of solids and fluids /". May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

34

Ray, Sherry Rene. "Issues Related to Implementing High-Fidelity Simulation in a Nursing Program". ScholarWorks, 2017. https://scholarworks.waldenu.edu/dissertations/4753.

Texto completo

Resumen

Due to the shortage of clinical sites, nursing educators, deans, and directors are compelled to implement alternative clinical solutions such as high-fidelity simulation (HFS). The problem is that nursing educators are often not prepared to implement HFS as a teaching strategy. Faculty readiness is imperative for a successful simulation program and student outcomes. Therefore, the purpose of this study was to investigate the perceptions and practices of faculty, deans, and directors on the implementation of HFS across the nursing curriculum. Kolb's experiential learning theory provided the theoretical support for both the teaching and learning required by faculty for a successful simulation program. The key research question was to investigate how nursing educators perceived the implementation of HFS across the curriculum and how nursing deans and directors provided support for integrating HFS throughout the curriculum. The study population included 13 nursing faculty and 7 deans using simulation at prelicensure programs. Data collection included interviews, observations of simulation labs, and document analysis. Data were analyzed using open and priori coding. Five themes emerged relating to need for faculty development, need for time, need for resources, need for space, and need for support. These findings were consistent with the literature. Based on the findings, a professional development program in simulation pedagogy was developed. The faculty development program could lead to a positive social change by reducing barriers and increasing the use of simulation. Increasing the use of simulation allows nursing students to practice clinical reasoning skills and gain confidence and competence with the goal of improving patient outcomes.

Los estilos APA, Harvard, Vancouver, ISO, etc.

35

Nehring, Wendy M. "A Synthesis of Theory and Nursing Research Using High-Fidelity Patient Simulation". Digital Commons @ East Tennessee State University, 2009. https://dc.etsu.edu/etsu-works/6717.

Texto completo

Resumen

Book Summary: High Fidelity Patient Simulation in Nursing Education is a comprehensive guide to developing and implementing a high-fidelity patient simulation in a clinical setting. It is a necessary primer for administrators and nursing programs starting out with this technology. It includes examples for setting up a simulator program for nurses, developing and implementing this technology into particular clinical and laboratory courses, and setting up refresher courses in hospital settings. The text features appendices and case scenarios.

Los estilos APA, Harvard, Vancouver, ISO, etc.

36

Takai, Tomohiro. "Simulation based design for high speed sea lift with waterjets by high fidelity urans approach". Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/748.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

37

Pluim, Jonathon Douglas. "DESIGN OF A HIGH FIDELITY WAKE SIMULATOR FOR RESEARCH USING LINEAR CASCADES". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244039010.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

38

Gust, Linda. "Building capability : impact of low and high-fidelity manikins on neonatal resuscitation simulation". Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Health Sciences, 2010, 2010. http://hdl.handle.net/10133/1288.

Texto completo

Resumen

Purpose: Does manikin fidelity affect learning outcomes in neonatal resuscitation simulation? Description: This experimental design accessed and randomly assigned health care professionals (HCP) (N=60), who completed Neonatal Resuscitation Program (NRP) recertification in a simulation lab. The experimental group used a high-fidelity manikin. The control group recertified using a low-fidelity manikin. Dependant variables included learning outcomes of confidence, skill performance, and knowledge. These were measured using the newly developed Neonatal Resuscitation Confidence Tool (NRCT), Megacode Assessment, and NRP written exam. Both groups underwent the same simulated resuscitation scenario. Outcome: A significant increase in confidence with simulation was found (p<.001). HCPs using the high-fidelity simulator did not have a significant increased level of confidence, knowledge or skill performance compared to using the low-fidelity simulator. However, there was a significant increase in confidence with repeated NRP courses (p=.003). Implications: The use of simulation for NRP is important to increase capability with increased practice intervals.
ix, 109 leaves : ill. ; 29 cm. --

Los estilos APA, Harvard, Vancouver, ISO, etc.

39

Denlea, Gregory Richard. "Evaluating Outcomes of High Fidelity Simulation Curriculum in a Community College Nursing Program". Thesis, Wingate University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10267212.

Texto completo

Resumen

This study took place at a Wake Technical Community College, a multi-campus institution in Raleigh, North Carolina. An evaluation of the return on investment in high fidelity simulation used by an associate degree of nursing program was conducted with valid and reliable instruments. The study demonstrated that comparable student outcomes are attainable when traditional clinical study is replaced with high fidelity simulation curriculum. Limited clinical practice space justifies the spread of simulation in college health science programs. North Carolina Administrative Code permits community colleges to replace 25% of traditional clinical with simulation. The lack of research on the cost effectiveness of high fidelity simulation has been cited as a barrier to its diffusion. Sound research demonstrating performance-based and patient-centric outcomes can provide governing bodies with evidence supporting the diffusion of high fidelity education.

Los estilos APA, Harvard, Vancouver, ISO, etc.

40

Coleman, Kerrie. "Pediatric Medication Administration Efficacy| A High-fidelity Pediatric Simulation Workshop for Pediatric Nurses". Thesis, Carlow University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10262152.

Texto completo

Resumen

The purpose of this scholarly project was to examine the use of a high-fidelity simulation workshop to improve accuracy with pediatric dosage calculations among practicing pediatric nurses. The NLN Jeffries Simulation Theory provided a framework for this descriptive quantitative project. A convenience sample of 15 pediatric nurses completed a 10-question pediatric dosage calculation pre-test, a high-fidelity simulation workshop, a 10-question pediatric dosage calculation post-test, and a post-simulation evaluation survey. In addition, a one-month follow-up 10-question pediatric dosage calculation post-test and a one-month follow-up post- high-fidelity simulation workshop survey were administered via Survey Monkey^©, in which 12 pediatric nurse participants completed. Pre-tests and post-tests were analyzed for central tendency and a t-test analysis was performed for statistical significance. Results revealed statistical significance between pre-test and post-test as well as statistical significance between post-test and one-month follow-up post-test. The Likert scale post-simulation survey and one month post-simulation survey were analyzed for central tendency. The results from the post simulation survey and one-month follow-up survey revealed the participants agreed to strongly agreed the high-fidelity simulation workshop impacted their proficiency and accuracy in calculating pediatric dosages. The findings from this project provides insights into the use of high-fidelity simulation as a continuing education tool for the practicing pediatric nurse in relation to pediatric medication efficacy.

Los estilos APA, Harvard, Vancouver, ISO, etc.

41

Nehring, Wendy M., Teressa Wexler, Faye Hughes y Audry Greenwell. "Faculty Development for the Use of High-Fidelity Patient Simulation: A Systematic Review". Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/ijhse/vol1/iss1/4.

Texto completo

Resumen

This is a systematic review of the research data between 1995 and June 2013 concerning faculty development in the use of high-fidelity patient simulation for health professionals and students with a search of the following databases: CINAHL, Nursing and Allied Health Collection: Comprehensive, OVID Medline, ScienceDirect, PubMed, Scopus, and ProQuest Dissertation/Theses Database. The primary search terms were high-fidelity patient simulation and faculty development. Reference lists from relevant articles were also reviewed. Twenty-five studies were included for this review. The majority of the studies were surveys with a few quasi-experimental designs. The themes were similar to those found in the non-research literature: strengths, incentives, barriers, use of faculty champions/simulation coordinator, and faculty development. The validity and reliability differed by study. There are numerous incentives and barriers to the use of high-fidelity patient simulation by faculty. Several examples of faculty development programs have been described in the literature but little evaluation has taken place beyond the end of the program. The goal of the use of high-fidelity patient simulation is to enhance the student’s knowledge, skills, and critical thinking in the care of patients. It is essential that the faculty are competent to provide instruction with high-fidelity patient simulation and therefore, the efficacy of these developmental programs need closer attention.

Los estilos APA, Harvard, Vancouver, ISO, etc.

42

Blakeslee, Janine Roth. "Effects of High-Fidelity Simulation on the Critical Thinking Skills of Baccalaureate Nursing Students". ScholarWorks, 2019. https://scholarworks.waldenu.edu/dissertations/6402.

Texto completo

Resumen

This project study addressed the decline in successful passing rates for the National Licensure Exam for Registered Nurses (NCLEX-RN) in a nursing program at a private university in the Midwestern United States. There is support from the literature for a connection between critical thinking skills of nursing students and successful passing of the NCLEX-RN. The purpose of this quantitative study was to examine whether significant differences existed in mean critical thinking skill scores across time within groups (pretest to posttest) and between groups (simulation versus written case studies), as measured by the Health Science Reasoning Test. Cognitive learning theory as interpreted by Ausubel along with the Paul Elder critical thinking model comprised the frameworks for this study. In a quantitative causal-comparative pretest/posttest design, baccalaureate junior nursing students (N = 69) were investigated. A repeated measures mixed analysis of variance indicated there was no statistically significant difference in participants' mean critical thinking scores across time within groups (pretest to posttest) or between a simulation group (n = 36) and a written case studies comparison group (n = 33). The use of high-fidelity simulation as a teaching strategy versus written case studies to increase critical thinking skills of nursing students was not supported. The resulting project deliverable is a skills-development workshop for nursing faculty that would focus on multiple methods (as opposed to one method) of evidence-based teaching strategies that have been shown to increase critical thinking of nursing students. This study promotes positive social change by examining factors that can strengthen critical thinking in nurses. Factors associated with critical thinking can be addressed in training for nurses to enhance patient safety and outcomes.

Los estilos APA, Harvard, Vancouver, ISO, etc.

43

Howard, Beverly J. "Computer-based versus high-fidelity mannequin simulation in developing clinical judgment in nursing education". Thesis, Capella University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3558176.

Texto completo

Resumen

The purpose of this study was to determine if students learn clinical judgment as effectively using computer-based simulations as when using high-fidelity mannequin simulations. There was a single research questions for this study: What is the difference in clinical judgment between participants completing high-fidelity human simulator mannequin simulation or computer-based simulation? A convenience sample of 50 associate degree nursing students in the last medical-surgical nursing course of their program were invited to participate in this study. Analysis of the demographic data confirmed the similarity of the two groups in terms of the potentially important confounding variables such as age, sex, education and prior healthcare experience. The score for each participant from the computer-based simulation (Simulation 2) and the percent of interventions completed in the high-fidelity human simulator simulation (Simulation 3) by each participant was added together to obtain an aggregate clinical judgment score for participants in Group C and Group M. Two-tailed t test for independent means was used to determine if a significant difference existed between the aggregate clinical judgment score for Group C and the aggregate clinical judgment score for Group M. Results from the test indicated that there was no difference between groups at the 95% confidence interval. The similarity of the clinical judgment scores of the computer-based simulation group to the scores of the high-fidelity mannequin simulation group indicates similar utility of the two instructional methods. The use of carefully planned and well-designed computer-based simulations can allow students to practice skills and develop confidence, self-efficacy and clinical judgment independently, freeing faculty for other instructional tasks.

Los estilos APA, Harvard, Vancouver, ISO, etc.

44

Babayan, Elaina Noelle. "High fidelity control and simulation of a three degrees-of-freedom wafer handling robot". Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54313.

Texto completo

Resumen

Wafer handling robotics are critical in semiconductor manufacturing to enable tight control of temperature, humidity, and particle contamination during processing. Closed-loop dynamic modeling during the robot design process ensures designs meet throughput and stability specifications prior to prototype hardware purchase. Dynamic models are also used in model-based control to improve performance. This thesis describes the generation and mathematical verification of a dynamic model for a three degrees-of-freedom wafer handling mechanism with one linear and two rotary axes. The dynamic plant model is integrated with motion and motor controller models, and the closed-loop performance is compared with experimental data. Models with rigid and flexible connections are compared, and the flexible connection models are shown to overall agree better with a measured step response. The simulation time increase from the addition of flexible connections can be minimized by modeling only the component stiffnesses that impact the closed-loop mechanism response. A method for selecting which elements to include based on controller bandwidth is presented and shown to significantly improve simulation times with minimal impact on model predictive performance.

Los estilos APA, Harvard, Vancouver, ISO, etc.

45

Azari, Pouyan. "An Orbit Control System for UWE-4 Using the High Fidelity Simulation Tool Orekit". Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-61409.

Texto completo

Resumen

Cubesats are picosatellites that have a mass of less than 1.3kg and have a shape of acube. As a result of their low cost of development and launch, cubesats are gainingpopularity in industry and academia. These satellites are also a cost-efective way forspace technology demonstrations. University of Würzburg has a longstanding cubesatprogram started with the launch of UWE-1 in 2005. This was followed by UWE-2 andUWE-3. Several technologies were tested and validated using the UWE platform. Thelast mission UWE-3 has successfully tested an attitude control system.In the next mission, UWE-4 will demonstrate an orbit control system. Being a picosatellite as small as this one (10 x 10 x 10cm 3 and 1kg) brings new challenges intodi↵erent aspects of satellite design, development, control and operation. The orbit con-trol of such a satellite is one of the problems that should be tackled. Being such a smallsatellite means having less propellant mass and much smaller thrusters than conventionalsatellites. These should be addressed in the orbit control. UWE-4 will take advantage of four NanoFEEP thrusters, on one side. Because of theiraccuracy and functionality, these thrusters can be used to implement a continuous thrustsystem. They are also a good choice because of their low energy usage. This work startswith the preparation that was needed to implement a control system. Then explains thestate of the art for continuous thrust control systems. Implements two di↵erent methods,based on perfect control and discusses the outcome. It discuses the limiting factors, likefuel mass, available electrical energy and their e↵ect on the controller performance andconcludes with recommendation for the future researches.
UWE-4

Los estilos APA, Harvard, Vancouver, ISO, etc.

46

Letzgus, Johannes [Verfasser] y Ewald [Akademischer Betreuer] Krämer. "High-fidelity simulation of dynamic stall on helicopter rotors / Johannes Letzgus ; Betreuer: Ewald Krämer". Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2021. http://d-nb.info/1237270774/34.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

47

Murray, Bethany A. "The Use of High-fidelity Simulation in Psychiatric and Mental Health Nursing Clinical Education". Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/ijhse/vol2/iss1/3.

Texto completo

Resumen

Background: High-fidelity simulation recreates real-life situations in a safe learning environment and encourages critical thinking in students. Published research in simulation in psychiatric/mental health nursing is sparse. Methods: Four scenarios exemplifying drug or alcohol abuse utilizing the computerized, mannequin SimMan® were implemented. Students evaluated their learning experience following completion of the simulation via a 20-item, Likert-scale survey which included open-ended questions. Results: Results were positive. Students rated all items on the survey as “agree” or “strongly agree” (Mean 4.77, SD=0.55). Conclusions: High fidelity clinical education simulations are an effective means of facilitating student learning of psychiatric and mental health clinical experiences. Students found simulation to be a useful and engaging means by which to learn to care for clients with drug or alcohol abuse disorders.

Los estilos APA, Harvard, Vancouver, ISO, etc.

48

Tutticci, Naomi F. "Measuring reflective thinking and self-efficacy after high fidelity simulation to optimise the reflective capacity of final year nursing students". Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/102966/4/Naomi_Tutticci_Thesis.pdf.

Texto completo

Resumen

Reflection is a cornerstone of effective registered nursing practice. This study developed a reliable and valid tool to measure critical reflection self-efficacy that was used in combination with a reflective thinking instrument to determine nursing students' reflective capacity. The balanced reflective practitioner model described by this study provided insight to both nursing students and educators about student's growth as reflective practitioners. The incorporation of nursing students in the debrief facilitator role had a significant effect on the ability of these students to reflectively think. This challenges the standard practice of academics as simulation debrief facilitators.

Los estilos APA, Harvard, Vancouver, ISO, etc.

49

Dunnington, Renee M. "The Nature and Determinants of Presence Among Nursing Students Participating in High Fidelity Human Patient Simulation". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1329957926.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

50

Garmann, Daniel J. "Characterization of the vortex formation and evolution about a revolving wing using high-fidelity simulation". University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367927773.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Tesis sobre el tema "High-Fidelity simulations"

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros