subject:(Floquet analysis)

1. Railton, Anna Dorothy. The structure and stability of vortices in astrophysical discs.

Degree: PhD, 2015, University of Cambridge

URL: https://www.repository.cam.ac.uk/handle/1810/252700https://www.repository.cam.ac.uk/bitstream/1810/252700/2/license.txt ; https://www.repository.cam.ac.uk/bitstream/1810/252700/3/license_rdf ; https://www.repository.cam.ac.uk/bitstream/1810/252700/4/thesis150615online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/252700/5/thesis150615online.pdf.jpg

► This thesis finds that vortex instabilities are not necessarily a barrier to their potential as sites for planetesimal formation. It is challenging to build planetesimals… (more)

▼ This thesis finds that vortex instabilities are not necessarily a barrier to their potential as sites for planetesimal formation. It is challenging to build planetesimals from dust within the lifetime of a protoplanetary disc and before such bodies spiral into the central star. Collecting matter in vortices is a promising mechanism for planetesimal growth, but little is known about their stability under these conditions. We therefore aim to produce a more complete understanding of the stability of these objects. Previous work primarily focusses on 2D vortices with elliptical streamlines, which we generalise. We investigate how non–constant vorticity and density power law profiles affect stability by applying linear perturbations to equilibrium solutions. We find that non–elliptical streamlines are associated with a shearing flow inside the vortex. A ‘saddle point instability’ is seen for elliptical–streamline vortices with small aspect ratios and we also find that this is true in general. However, only higher aspect ratio vortices act as dust traps. For constant–density vortices with a concentrated vorticity source we find parametric instability bands at these aspect ratios. Models with a density excess show many narrow bands, though with less strongly growing modes than the constant–density solutions. This implies that dust particles attracted to a vortex core may well encounter parametric instabilities, but this does not necessarily prevent dust–trapping. We also study the stability and lifetime of vortex models with a 2D flow in three dimensions. Producing nearly–incompressible 3D models of columnar vortices, we find that weaker vortices persist for longer times in both stratified and unstratified shearing boxes, and stratification is destabilising. The long survival time for weak, elongated vortices makes it easier for processes to create and maintain the vortex. This means that vortices with a large enough aspect ratio have a good chance of surviving and trapping dust for sufficient time in order to build planetesimals.

Subjects/Keywords: vortices; floquet; stability analysis; planetesimal formation; protoplanetary discs

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APA (6^th Edition):

Railton, A. D. (2015). The structure and stability of vortices in astrophysical discs. (Doctoral Dissertation). University of Cambridge. Retrieved from https://www.repository.cam.ac.uk/handle/1810/252700https://www.repository.cam.ac.uk/bitstream/1810/252700/2/license.txt ; https://www.repository.cam.ac.uk/bitstream/1810/252700/3/license_rdf ; https://www.repository.cam.ac.uk/bitstream/1810/252700/4/thesis150615online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/252700/5/thesis150615online.pdf.jpg

Chicago Manual of Style (16^th Edition):

Railton, Anna Dorothy. “The structure and stability of vortices in astrophysical discs.” 2015. Doctoral Dissertation, University of Cambridge. Accessed March 05, 2021. https://www.repository.cam.ac.uk/handle/1810/252700https://www.repository.cam.ac.uk/bitstream/1810/252700/2/license.txt ; https://www.repository.cam.ac.uk/bitstream/1810/252700/3/license_rdf ; https://www.repository.cam.ac.uk/bitstream/1810/252700/4/thesis150615online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/252700/5/thesis150615online.pdf.jpg.

MLA Handbook (7^th Edition):

Railton, Anna Dorothy. “The structure and stability of vortices in astrophysical discs.” 2015. Web. 05 Mar 2021.

Vancouver:

Railton AD. The structure and stability of vortices in astrophysical discs. [Internet] [Doctoral dissertation]. University of Cambridge; 2015. [cited 2021 Mar 05]. Available from: https://www.repository.cam.ac.uk/handle/1810/252700https://www.repository.cam.ac.uk/bitstream/1810/252700/2/license.txt ; https://www.repository.cam.ac.uk/bitstream/1810/252700/3/license_rdf ; https://www.repository.cam.ac.uk/bitstream/1810/252700/4/thesis150615online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/252700/5/thesis150615online.pdf.jpg.

Council of Science Editors:

Railton AD. The structure and stability of vortices in astrophysical discs. [Doctoral Dissertation]. University of Cambridge; 2015. Available from: https://www.repository.cam.ac.uk/handle/1810/252700https://www.repository.cam.ac.uk/bitstream/1810/252700/2/license.txt ; https://www.repository.cam.ac.uk/bitstream/1810/252700/3/license_rdf ; https://www.repository.cam.ac.uk/bitstream/1810/252700/4/thesis150615online.pdf.txt ; https://www.repository.cam.ac.uk/bitstream/1810/252700/5/thesis150615online.pdf.jpg

University of Cambridge

2. Railton, Anna Dorothy. The structure and stability of vortices in astrophysical discs.

Degree: PhD, 2015, University of Cambridge

URL: https://doi.org/10.17863/CAM.16146 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675903

► This thesis finds that vortex instabilities are not necessarily a barrier to their potential as sites for planetesimal formation. It is challenging to build planetesimals… (more)

▼ This thesis finds that vortex instabilities are not necessarily a barrier to their potential as sites for planetesimal formation. It is challenging to build planetesimals from dust within the lifetime of a protoplanetary disc and before such bodies spiral into the central star. Collecting matter in vortices is a promising mechanism for planetesimal growth, but little is known about their stability under these conditions. We therefore aim to produce a more complete understanding of the stability of these objects. Previous work primarily focusses on 2D vortices with elliptical streamlines, which we generalise. We investigate how non?constant vorticity and density power law profiles affect stability by applying linear perturbations to equilibrium solutions. We find that non?elliptical streamlines are associated with a shearing flow inside the vortex. A ?saddle point instability? is seen for elliptical?streamline vortices with small aspect ratios and we also find that this is true in general. However, only higher aspect ratio vortices act as dust traps. For constant?density vortices with a concentrated vorticity source we find parametric instability bands at these aspect ratios. Models with a density excess show many narrow bands, though with less strongly growing modes than the constant?density solutions. This implies that dust particles attracted to a vortex core may well encounter parametric instabilities, but this does not necessarily prevent dust?trapping. We also study the stability and lifetime of vortex models with a 2D flow in three dimensions. Producing nearly?incompressible 3D models of columnar vortices, we find that weaker vortices persist for longer times in both stratified and unstratified shearing boxes, and stratification is destabilising. The long survival time for weak, elongated vortices makes it easier for processes to create and maintain the vortex. This means that vortices with a large enough aspect ratio have a good chance of surviving and trapping dust for sufficient time in order to build planetesimals.

Subjects/Keywords: 500; vortices; floquet; stability analysis; planetesimal formation; protoplanetary discs

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Railton, A. D. (2015). The structure and stability of vortices in astrophysical discs. (Doctoral Dissertation). University of Cambridge. Retrieved from https://doi.org/10.17863/CAM.16146 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675903

Chicago Manual of Style (16^th Edition):

Railton, Anna Dorothy. “The structure and stability of vortices in astrophysical discs.” 2015. Doctoral Dissertation, University of Cambridge. Accessed March 05, 2021. https://doi.org/10.17863/CAM.16146 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675903.

MLA Handbook (7^th Edition):

Railton, Anna Dorothy. “The structure and stability of vortices in astrophysical discs.” 2015. Web. 05 Mar 2021.

Vancouver:

Railton AD. The structure and stability of vortices in astrophysical discs. [Internet] [Doctoral dissertation]. University of Cambridge; 2015. [cited 2021 Mar 05]. Available from: https://doi.org/10.17863/CAM.16146 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675903.

Council of Science Editors:

Railton AD. The structure and stability of vortices in astrophysical discs. [Doctoral Dissertation]. University of Cambridge; 2015. Available from: https://doi.org/10.17863/CAM.16146 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675903

University of Melbourne

3. McCaw, James M. Quantum chaos: spectral analysis of Floquet operators.

Degree: 2004, University of Melbourne

URL: http://hdl.handle.net/11343/38911

► The Floquet operator, defined as the time-evolution operator over one period, plays a central role in the work presented in this thesis on periodically perturbed… (more)

Subjects/Keywords: spectral analysis; quantum chaos; Floquet operator; number theory

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

McCaw, J. M. (2004). Quantum chaos: spectral analysis of Floquet operators. (Doctoral Dissertation). University of Melbourne. Retrieved from http://hdl.handle.net/11343/38911

Chicago Manual of Style (16^th Edition):

McCaw, James M. “Quantum chaos: spectral analysis of Floquet operators.” 2004. Doctoral Dissertation, University of Melbourne. Accessed March 05, 2021. http://hdl.handle.net/11343/38911.

MLA Handbook (7^th Edition):

McCaw, James M. “Quantum chaos: spectral analysis of Floquet operators.” 2004. Web. 05 Mar 2021.

Vancouver:

McCaw JM. Quantum chaos: spectral analysis of Floquet operators. [Internet] [Doctoral dissertation]. University of Melbourne; 2004. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11343/38911.

Council of Science Editors:

McCaw JM. Quantum chaos: spectral analysis of Floquet operators. [Doctoral Dissertation]. University of Melbourne; 2004. Available from: http://hdl.handle.net/11343/38911

University of Oklahoma

4. Bhowmik, Lal Mohan. Applications of Floquet Analysis to Modern Phased Array Antennas.

Degree: PhD, 2019, University of Oklahoma

URL: http://hdl.handle.net/11244/321405

► Next generation radar technology is based on phased array technology and provides remarkable scanning flexibility and spatial search capability for the multifunction weather and air… (more)

▼ Next generation radar technology is based on phased array technology and provides remarkable scanning flexibility and spatial search capability for the multifunction weather and air surveillance radar systems. The future weather radar is comprised of thousands of antenna elements and requires strict polarization purity, grating lobe free system, low sidelobe levels, suppressed surface waves, low cross-polarization, with beam shape requirements. To address these demands is a serious challenge. Over the past few decades, phased array radar technology has been a tremendous advancement in search for future radar technology. With the blessing of modern computational electromagnetic tools, the theory behind the electromagnetic and circuit-level behavior of large-scale phased array system opened the door to analyze the wide variety of multi-layered, complex system of large arrays. However, numerous challenges still remained unsolved for large scale development. One such challenge in integrating a large phased array is the threat of grating lobes that are introduced by unavoidable disturbances to the periodic structure at the seams between mechanical sub-array modules. In particular, gaps in the ground plane may interrupt the natural currents between elements, leading to radiation from periodic sources that are spaced at regular distances that are typically many wavelengths apart. In order to quantify these grating lobe effects, an appropriate analysis framework and accurate model are of utmost importance. The model must capture all surface wave and mutual coupling between elements, and the analysis must have a clear formulation that allows for the calculation of worst-case grating lobe levels as well as differences in active reflection as a function of location within a sub-array. To accurately predict those effects, this dissertation work applied a modern method called Floquet framework, coupling with full wave solver to explore the grating lobe effects in infinite arrays of sub-arrays, with each physical sub-array potentially separated from the others by a gap or discontinuity in the ground plane. Calculations are then performed to extract active reflection coefficients and grating lobe levels from the resulting Floquet mode scattering parameters. Additionally, this Floquet framework is expanded from broadside to any scan angles in space. In the mathematical framework, the surface equivalence theorem based on Huygens’s equivalence principle is applied to authenticate its findings. From the simulation results, it is evident that the grating lobe amplitude level emerged to around 30 dB in the E-plane scan and E- plane grating lobes for a patch array. This is due to natural current disruption in between sub-arrays in the ground plane gap and it is very strong in the E-plane, leading to the potential for low-level grating lobe effects. The other planes and scan angles show less significant effects. It was found that the measurements qualitatively follow the simulated results. The Floquet-based method may therefore be used… Advisors/Committee Members: Fulton, Caleb (advisor), Remling, Christian (committee member), Bluestein, Howard (committee member), Goodman, Nathan (committee member), Sigmarsson, Hjalti (committee member), Ruyle, Jessica (committee member).

Subjects/Keywords: Scan blindness; Creeping waves; Cylindrical Electromagnetic Bandgap (EBG) structures; Floquet analysis; Grating lobe; MPAR; CPPAR; Phased array

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bhowmik, L. M. (2019). Applications of Floquet Analysis to Modern Phased Array Antennas. (Doctoral Dissertation). University of Oklahoma. Retrieved from http://hdl.handle.net/11244/321405

Chicago Manual of Style (16^th Edition):

Bhowmik, Lal Mohan. “Applications of Floquet Analysis to Modern Phased Array Antennas.” 2019. Doctoral Dissertation, University of Oklahoma. Accessed March 05, 2021. http://hdl.handle.net/11244/321405.

MLA Handbook (7^th Edition):

Bhowmik, Lal Mohan. “Applications of Floquet Analysis to Modern Phased Array Antennas.” 2019. Web. 05 Mar 2021.

Vancouver:

Bhowmik LM. Applications of Floquet Analysis to Modern Phased Array Antennas. [Internet] [Doctoral dissertation]. University of Oklahoma; 2019. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/11244/321405.

Council of Science Editors:

Bhowmik LM. Applications of Floquet Analysis to Modern Phased Array Antennas. [Doctoral Dissertation]. University of Oklahoma; 2019. Available from: http://hdl.handle.net/11244/321405

5. Gioria, Rafael dos Santos. Estudo da estabilidade secundária da esteira de um cilindro em oscilação forçada.

Degree: PhD, Engenharia Mecânica de Energia de Fluidos, 2010, University of São Paulo

URL: http://www.teses.usp.br/teses/disponiveis/3/3150/tde-11082010-123926/ ;

►

Esta tese apresenta o estudo da transição para um escoamento tridimensional da esteira de um cilindro oscilando. Esta é a transição secundária do escoamento ao… (more)

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Esta tese apresenta o estudo da transição para um escoamento tridimensional da esteira de um cilindro oscilando. Esta é a transição secundária do escoamento ao redor de um cilindro, sendo a primária a própria esteira de von Kármán. A investigação é realizada na mesma faixa de número de Reynolds (Re) que ocorre a transição da esteira de um cilindro fixo: 200 Re 400. O estudo envolve simulações numéricas diretas bi- e tridimensionais do escoamento incompressível ao redor de um cilindro oscilando usando o método dos elementos espectrais. A transição também é analisada através do estudo de estabilidade linear do escoamento. O método de Gaston Floquet é adequado para a análise de estabilidade a perturbações tridimensionais devido à periodicidade característica da esteira de von Kármán. Além disto, o método é mais geral e não é aplicado somente a equações autônomas com soluções periódicas: ele também pode ser usado em análises cujo campo base é estacionário como a análise da transição primária da esteira de um cilindro. Mostra-se que a transição da esteira para tridimensionalidade é influenciada pela oscilação do cilindro. As oscilações podem atrasar a transição quando em amplitudes baixas e com escoamento a um número de Reynolds até 260. Em outros casos, a transição é similar à observada no escoamento ao redor um cilindro fixo. Além disso, quando há mudança de padrões de desprendimento de vórtices devido às oscilações, desencadeiam-se modos instáveis diferentes dos observados na esteira de um cilindro fixo. A comparação dos resultados da análise de estabilidade de Floquet com simulações numéricas diretas e experimentos publicados mostra na maioria dos casos que, apesar de ser uma análise de estabilidade linear, muitas características da análise persistem além do limiar de estabilidade. As situações com discrepâncias são identificadas nesta tese, como padrão de desprendimento diferentes em simulações bi- e tridimensionais na mesma situação. As causa das discrepâncias são estudadas através das simulações numéricas diretas e considerações sobre o sistema linearizado e a abrangência da análise de estabilidade. Em adição, mostra-se que há um limiar de amplitude de oscilação acima do qual a dinâmica da esteira, e portanto a transição secundária, é afetada. Abaixo deste limiar, retoma-se o comportamento do escoamento ao redor de um cilindro fixo.

This thesis presents the investigation of the transition to a three-dimensional flow in the wake of an oscillating circular cylinder. This is the secondary transition of the flow around a circular cylinder, while the primary transition leads to the von Kármán wake. The investigative work is performed in the Reynolds number (Re) range which occurs the secondary transition of the wake o a circular cylinder: 200 Re 400. The study consists of two- and three-dimensional direct numerical simulations of the incompressible flow around an oscillating circular cylinder by means of the spectral/hp method. The transition is also analyzed through linear stability study of the flow. The Gaston…

Advisors/Committee Members: Meneghini, Julio Romano.

Subjects/Keywords: Análise de estabilidade de Floquet; Escoamento ao redor de um cilindro oscilando; Floquet stability analysis; Flow around an oscillating circular cylinder; Método dos elementos espectrais; Secondary transition of a wake; Spectral/hp element method; Transição secundária da esteira

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Gioria, R. d. S. (2010). Estudo da estabilidade secundária da esteira de um cilindro em oscilação forçada. (Doctoral Dissertation). University of São Paulo. Retrieved from http://www.teses.usp.br/teses/disponiveis/3/3150/tde-11082010-123926/ ;

Chicago Manual of Style (16^th Edition):

Gioria, Rafael dos Santos. “Estudo da estabilidade secundária da esteira de um cilindro em oscilação forçada.” 2010. Doctoral Dissertation, University of São Paulo. Accessed March 05, 2021. http://www.teses.usp.br/teses/disponiveis/3/3150/tde-11082010-123926/ ;.

MLA Handbook (7^th Edition):

Gioria, Rafael dos Santos. “Estudo da estabilidade secundária da esteira de um cilindro em oscilação forçada.” 2010. Web. 05 Mar 2021.

Vancouver:

Gioria RdS. Estudo da estabilidade secundária da esteira de um cilindro em oscilação forçada. [Internet] [Doctoral dissertation]. University of São Paulo; 2010. [cited 2021 Mar 05]. Available from: http://www.teses.usp.br/teses/disponiveis/3/3150/tde-11082010-123926/ ;.

Council of Science Editors:

Gioria RdS. Estudo da estabilidade secundária da esteira de um cilindro em oscilação forçada. [Doctoral Dissertation]. University of São Paulo; 2010. Available from: http://www.teses.usp.br/teses/disponiveis/3/3150/tde-11082010-123926/ ;

6. Hussein, Ahmed Abd Elmonem Ahmed. Dynamical System Representation and Analysis of Unsteady Flow and Fluid-Structure Interactions.

Degree: PhD, Engineering Mechanics, 2018, Virginia Tech

URL: http://hdl.handle.net/10919/85626

► We present modeling approaches of the interaction between flying or swimming bodies and the surrounding fluids. We consider their stability as they perform special maneuvers.… (more)

Subjects/Keywords: Finite-State Unsteady Aerodynamics; Lagrangian; Point Vortices; Flutter; Aeroelasticity; Finite Element Method; Flexibility; Hydroelasticity; Nonlinear Time-Periodic Dynamics; Floquet Analysis; Optimal Control

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hussein, A. A. E. A. (2018). Dynamical System Representation and Analysis of Unsteady Flow and Fluid-Structure Interactions. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/85626

Chicago Manual of Style (16^th Edition):

Hussein, Ahmed Abd Elmonem Ahmed. “Dynamical System Representation and Analysis of Unsteady Flow and Fluid-Structure Interactions.” 2018. Doctoral Dissertation, Virginia Tech. Accessed March 05, 2021. http://hdl.handle.net/10919/85626.

MLA Handbook (7^th Edition):

Hussein, Ahmed Abd Elmonem Ahmed. “Dynamical System Representation and Analysis of Unsteady Flow and Fluid-Structure Interactions.” 2018. Web. 05 Mar 2021.

Vancouver:

Hussein AAEA. Dynamical System Representation and Analysis of Unsteady Flow and Fluid-Structure Interactions. [Internet] [Doctoral dissertation]. Virginia Tech; 2018. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/10919/85626.

Council of Science Editors:

Hussein AAEA. Dynamical System Representation and Analysis of Unsteady Flow and Fluid-Structure Interactions. [Doctoral Dissertation]. Virginia Tech; 2018. Available from: http://hdl.handle.net/10919/85626

INP Toulouse

7. Hamdi, Bilel. Modélisation des circuits périodiques et quasi-périodiques alimentés par des sources arbitraires : Optimization of UPS lighting systems based on DC low voltage bus.

Degree: Docteur es, Micro-ondes, Électromagnétisme et Optoélectronique, 2015, INP Toulouse

URL: http://www.theses.fr/2015INPT0150

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Les réseaux d’antennes planaires sont réputés par leur grande directivité et leur facilité de mise en œuvre qui offre la possibilité d’avoir un diagramme de… (more)

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Les réseaux d’antennes planaires sont réputés par leur grande directivité et leur facilité de mise en œuvre qui offre la possibilité d’avoir un diagramme de rayonnement commandable. Cependant l’étude globale tenant compte des différents couplages EM par une théorie électromagnétique rigoureuse nécessite un espace mémoire important et un temps de calcul considérable. Pour surmonter à ces inconvénients, nous proposons d’introduire une nouvelle approche théorique basée sur le théorème de Floquet permettant la réduction du volume d’analyse EM au niveau d’une seule cellule élémentaire. Nous allons focaliser notre étude à la détermination des termes de couplage dans une configuration répartie dans une trame presque-périodique et en particulier pour les réseaux d’antennes périodiques et quasi-périodiques alimentés par des sources arbitraires. Dans ce cas, nous utiliserons les décompositions en modes de Floquet (adaptées aux structures périodiques) pour extraire la matrice de couplage [S]. Ces décompositions sont des concepts établis de longue date et a priori démontrés par de supports théoriques solides. Par conséquent, cette analyse modale permet de simplifier la résolution du problème considéré surtout quand les éléments rayonnants sont fortement couplés. Une seule méthode numérique est adoptée afin de modéliser la structure proposée : la méthode des moments combinée avec le circuit équivalent généralisé : MoM-GEC. La validation de cette dernière sera réalisée par comparaison avec d’autres méthodes numériques exactes

Planar antenna arrays are renowned for their high directivity and ease of implementation, which offers the possibility of having a controllable radiation pattern. However the global study taking into account the different EM couplings by a rigorous electromagnetic theory requires a large memory space and a considerable computation time. To overcome these drawbacks, we propose to introduce a new theoretical approach based on the Floquet theorem allowing the reduction of the EM analysis volume at the level of a single elementary cell (basic cell). We will focus our study on the determination of coupling terms in a distributed configuration in an almost-periodic frame and in particular for periodic and quasi-periodic antenna arrays fed by arbitrary sources. In this case, we will use Floquet mode decompositions (adapted to periodic structures) to extract the coupling matrix [S]. These decompositions are concepts established for a long time and a priori demonstrated by solid theoretical supports. Consequently, this modal analysis makes it possible to simplify considerably the resolution of the problem, especially when the radiating elements are strongly coupled. A single numerical method is adopted in order to model the proposed structure: the method of moments combined with the generalized equivalent circuit: MoM-GEC. Validation of the latter will be done by comparison with other exact numerical methods.

Advisors/Committee Members: Tao, Junwu (thesis director), Aguili, Toufik (thesis director).

Subjects/Keywords: Analyse de Floquet; Murs périodiques; Méthode des moments; Circuits équivalents généralisés; Couplage mutuel; Paramètres S; Réseaux uni dimensionnelle; Réseaux Bi dimensionnelle; Structure fini; Structure infini; Réseaux presque-périodiques; Réseaux quasi-périodiques; Floquet analysis; Periodic walls; Moment method; Generalized equivalent circuits; Mutual coupling; S-Parameters; Uni-dimensional networks; Bi-dimensional networks; Finite structure; Infinite structure; Almost periodic networks; Quasi-periodic networks

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hamdi, B. (2015). Modélisation des circuits périodiques et quasi-périodiques alimentés par des sources arbitraires : Optimization of UPS lighting systems based on DC low voltage bus. (Doctoral Dissertation). INP Toulouse. Retrieved from http://www.theses.fr/2015INPT0150

Chicago Manual of Style (16^th Edition):

Hamdi, Bilel. “Modélisation des circuits périodiques et quasi-périodiques alimentés par des sources arbitraires : Optimization of UPS lighting systems based on DC low voltage bus.” 2015. Doctoral Dissertation, INP Toulouse. Accessed March 05, 2021. http://www.theses.fr/2015INPT0150.

MLA Handbook (7^th Edition):

Hamdi, Bilel. “Modélisation des circuits périodiques et quasi-périodiques alimentés par des sources arbitraires : Optimization of UPS lighting systems based on DC low voltage bus.” 2015. Web. 05 Mar 2021.

Vancouver:

Hamdi B. Modélisation des circuits périodiques et quasi-périodiques alimentés par des sources arbitraires : Optimization of UPS lighting systems based on DC low voltage bus. [Internet] [Doctoral dissertation]. INP Toulouse; 2015. [cited 2021 Mar 05]. Available from: http://www.theses.fr/2015INPT0150.

Council of Science Editors:

Hamdi B. Modélisation des circuits périodiques et quasi-périodiques alimentés par des sources arbitraires : Optimization of UPS lighting systems based on DC low voltage bus. [Doctoral Dissertation]. INP Toulouse; 2015. Available from: http://www.theses.fr/2015INPT0150

Virginia Tech

8. Mazumder, Sudip K. Nonlinear Analysis and Control of Standalone, Parallel DC-DC, and Parallel Multi-Phase PWM Converters.

Degree: PhD, Electrical and Computer Engineering, 2001, Virginia Tech

URL: http://hdl.handle.net/10919/28690

► Applications of distributed-power systems are on the rise. They are already used in telecommunication power supplies, aircraft and shipboard power-distribution systems, motor drives, plasma applications,… (more)

▼ Applications of distributed-power systems are on the rise. They are already used in telecommunication power supplies, aircraft and shipboard power-distribution systems, motor drives, plasma applications, and they are being considered for numerous other applications. The successful operation of these multi-converter systems relies heavily on a stable design. Conventional analyses of power converters are based on averaged models, which ignore the fast-scale instability and analyze the stability on a reduced-order manifold. As such, validity of the averaged models varies with the switching frequency even for the same topological structure. The prevalent procedure for analyzing the stability of switching converters is based on linearized smooth averaged (small-signal) models. Yet there are systems (in active use) that yield a non-smooth averaged model. Even for systems for which smooth averaged models are realizable, small-signal analyses of the nominal solution/orbit do not provide anything about three important characteristics: region of attraction of the nominal solution, dependence of the converter dynamics on the initial conditions of the states, and the post-instability dynamics. As such, converters designed based on small-signal analyses may be conservative. In addition, linear controllers based on such analysis may not be robust and optimal. Clearly, there is a need to analyze the stability of power converters from a different perspective and design nonlinear controllers for such hybrid systems. In this Dissertation, using bifurcation analysis and Lyapunov's method, we analyze the stability and dynamics of some of the building blocks of distributed-power systems, namely standalone, integrated, and parallel converters. Using analytical and experimental results, we show some of the differences between the conventional and new approaches for stability analyses of switching converters and demonstrate the shortcomings of some of the existing results. Furthermore, using nonlinear analyses we attempt to answer three fundamental questions: when does an instability occur, what is the mechanism of the instability, and what happens after the instability? Subsequently, we develop nonlinear controllers to stabilize parallel dc-dc and parallel multi-phase converters. The proposed controllers for parallel dc-dc converters combine the concepts of multiple-sliding-surface and integral-variable-structure control. They are easy to design, robust, and have good transient and steady-state performances. Furthermore, they achieve a constant switching frequency within the boundary layer and hence can be operated in interleaving or synchronicity modes. The controllers developed for parallel multi-phase converters retain many of the above features. In addition, they do not require any communication between the modules; as such, they have high redundancy. One of these control schemes combines space-vector modulation and variable-structure control. It achieves constant switching frequency within the boundary layer and a good… Advisors/Committee Members: VanLandingham, Hugh F. (committee member), Baumann, William T. (committee member), Lai, Jih-Sheng Jason (committee member), Boroyevich, Dushan (committeecochair), Nayfeh, Ali H. (committeecochair).

Subjects/Keywords: Lyapunov's Method; Sliding Surface; Bifurcation Theory; Modeling; Nonlinear Control; Parallel Converters; Multi-Phase Converters; Differential Inclusion; DC-DC Converters; Stability Analysis; Power Electronics; Floquet Theory

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Mazumder, S. K. (2001). Nonlinear Analysis and Control of Standalone, Parallel DC-DC, and Parallel Multi-Phase PWM Converters. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/28690

Chicago Manual of Style (16^th Edition):

Mazumder, Sudip K. “Nonlinear Analysis and Control of Standalone, Parallel DC-DC, and Parallel Multi-Phase PWM Converters.” 2001. Doctoral Dissertation, Virginia Tech. Accessed March 05, 2021. http://hdl.handle.net/10919/28690.

MLA Handbook (7^th Edition):

Mazumder, Sudip K. “Nonlinear Analysis and Control of Standalone, Parallel DC-DC, and Parallel Multi-Phase PWM Converters.” 2001. Web. 05 Mar 2021.

Vancouver:

Mazumder SK. Nonlinear Analysis and Control of Standalone, Parallel DC-DC, and Parallel Multi-Phase PWM Converters. [Internet] [Doctoral dissertation]. Virginia Tech; 2001. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/10919/28690.

Council of Science Editors:

Mazumder SK. Nonlinear Analysis and Control of Standalone, Parallel DC-DC, and Parallel Multi-Phase PWM Converters. [Doctoral Dissertation]. Virginia Tech; 2001. Available from: http://hdl.handle.net/10919/28690

Texas A&M University

9. Somayajula, Abhilash Sharma. Reliability Assessment of Hull Forms Susceptible to Parametric Roll in Irregular Seas.

Degree: PhD, Ocean Engineering, 2017, Texas A&M University

URL: http://hdl.handle.net/1969.1/161436

► Traditionally ships are designed to be symmetric about their centerline which makes head seas a very safe heading for roll motion stability. However, in the… (more)

▼ Traditionally ships are designed to be symmetric about their centerline which makes head seas a very safe heading for roll motion stability. However, in the recent years several incidents of large amplitude roll motion in head seas have been reported which have later been attributed to parametric roll. Parametric roll motion is a phenomenon in which a ship exhibits a large amplitude of roll motion even when it is moving into head seas with no direct excitation. This phenomenon is particularly an issue for modern high-speed fine form container ships and has gained attention relatively recently. This instability is dangerous because of its manifestation in counter-intuitive headings. Also the roll amplitude during parametric roll rises exponentially with time which gives ship captains and masters very less time to react. While this instability has been studied extensively in regular waves, its manifestation in irregular seas has not received sufficient attention. This dissertation aims at the development of design criteria based on analytical techniques which can help a designer quickly quantify the stability of a vessel to parametric excitation. For accurate simulation of parametric response of a vessel/platform in irregular seas, an in-house time domain simulation program has been developed and validated against available experiments. The roll equation of motion is then simplified into a single degree of freedom model for analytical assessment. The existing single degree of freedom models in the literature are compared against the time domain simulation tool to gain an understanding of the extent to which the simplified models capture the dynamics of the phenomenon. In order to improve the roll modeling, a new approach is suggested to overcome some of the limitations of the existing models. This new model is then investigated using two analytical approaches, one from the theory of nonlinear dynamical systems and the other from stochastic dynamics to come up with two independent measures of stability. Both of these measures are used to demonstrate their potential as a design criteria which can be used by a ship designer. A comparison of the two methods for a variety of cases is undertaken to demonstrate the similar trends they exhibit. Advisors/Committee Members: Falzarano, Jeffrey M (advisor), Kim, Moo-Hyun (committee member), Mercier, Richard S (committee member), Palazzolo, Alan B (committee member).

Subjects/Keywords: Large amplitude motion; Time domain simulation; Irregular sea; Nonlinear Froude Krylov; Nonlinear hydrostatics; Impulse response function; Parametric roll; Parametric response; Mathieu instability; Floquet theory; Ergodicity; Non-Gaussian response; Single degree of freedom roll model; Volterra GZ; Volterra GM; Improved Grim effective wave; Nonlinear dynamical systems; Melnikov function; Rate of phase space flux; Random dynamics; Stochastic dynamics; Stochastic averaging; Markov approximation; Fokker Plank Kolmogorov equation; Pontryagin equation; Mean first passage time; Mean first escape rate; Lyapunov exponent; Sensitivity analysis; Reliability analysis; Long term stability analysis

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Somayajula, A. S. (2017). Reliability Assessment of Hull Forms Susceptible to Parametric Roll in Irregular Seas. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/161436

Chicago Manual of Style (16^th Edition):

Somayajula, Abhilash Sharma. “Reliability Assessment of Hull Forms Susceptible to Parametric Roll in Irregular Seas.” 2017. Doctoral Dissertation, Texas A&M University. Accessed March 05, 2021. http://hdl.handle.net/1969.1/161436.

MLA Handbook (7^th Edition):

Somayajula, Abhilash Sharma. “Reliability Assessment of Hull Forms Susceptible to Parametric Roll in Irregular Seas.” 2017. Web. 05 Mar 2021.

Vancouver:

Somayajula AS. Reliability Assessment of Hull Forms Susceptible to Parametric Roll in Irregular Seas. [Internet] [Doctoral dissertation]. Texas A&M University; 2017. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/1969.1/161436.

Council of Science Editors:

Somayajula AS. Reliability Assessment of Hull Forms Susceptible to Parametric Roll in Irregular Seas. [Doctoral Dissertation]. Texas A&M University; 2017. Available from: http://hdl.handle.net/1969.1/161436

University of Southern California

10. Ghaemi Oskouei, Babak. Stability of body-vortex systems: Application to aquatic locomotion.

Degree: PhD, Aerospace & Mechanical Engineering (Dynamics & Control), 2013, University of Southern California

URL: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/451808/rec/6029

► Mathematical modeling and analysis of biological systems such as swimming and flying is an interdisciplinary research field with an extensive range of applications including the… (more)

Subjects/Keywords: point vortex; dynamical systems; stability analysis; vortex wake; fish; fish schooling; solid body; fluid; interaction; floquet theory; inviscid; incompressible; irrotational flow; 2D flow; ellipse; circle; Kirchhoff Routh; classical; Milne Thomson; circle theorem; complex potential; velocity; kinematics; submerged; Grobli; periodic; thrust; drag; von Karman; street; mid wake; streamline; pattern; topology; time scale; bifurcation; Doubly-Infinite Array; zeta function; vortex lattice; orientation control; elongated body; staggered street; symmetric street; convergence; integral test; dynamics; control; ideal fluid; aquatic locomotion; propulsion

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ghaemi Oskouei, B. (2013). Stability of body-vortex systems: Application to aquatic locomotion. (Doctoral Dissertation). University of Southern California. Retrieved from http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/451808/rec/6029

Chicago Manual of Style (16^th Edition):

Ghaemi Oskouei, Babak. “Stability of body-vortex systems: Application to aquatic locomotion.” 2013. Doctoral Dissertation, University of Southern California. Accessed March 05, 2021. http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/451808/rec/6029.

MLA Handbook (7^th Edition):

Ghaemi Oskouei, Babak. “Stability of body-vortex systems: Application to aquatic locomotion.” 2013. Web. 05 Mar 2021.

Vancouver:

Ghaemi Oskouei B. Stability of body-vortex systems: Application to aquatic locomotion. [Internet] [Doctoral dissertation]. University of Southern California; 2013. [cited 2021 Mar 05]. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/451808/rec/6029.

Council of Science Editors:

Ghaemi Oskouei B. Stability of body-vortex systems: Application to aquatic locomotion. [Doctoral Dissertation]. University of Southern California; 2013. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll127/id/451808/rec/6029

ETH Zürich

11. Scholz, Ingo Gerhard. Operator-based floquet theory and its applications to solid-state NMR.

Degree: 2010, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/152030

Subjects/Keywords: NMR-MIKROSKOPIE, NMR-ABBILDUNDSVERFAHREN; HAMILTONOPERATOR (QUANTENTHEORIE); NUMERISCHE SIMULATION UND MATHEMATISCHE MODELLRECHNUNG; FLOQUETTHEORIE (ANALYSIS); NMR MICROSCOPY, NMR IMAGING; HAMILTON OPERATOR (QUANTUM THEORY); NUMERICAL SIMULATION AND MATHEMATICAL MODELING; FLOQUET THEORY (MATHEMATICAL ANALYSIS); info:eu-repo/classification/ddc/570; info:eu-repo/classification/ddc/530; info:eu-repo/classification/ddc/530; Life sciences; Physics; Physics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Scholz, I. G. (2010). Operator-based floquet theory and its applications to solid-state NMR. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/152030

Chicago Manual of Style (16^th Edition):

Scholz, Ingo Gerhard. “Operator-based floquet theory and its applications to solid-state NMR.” 2010. Doctoral Dissertation, ETH Zürich. Accessed March 05, 2021. http://hdl.handle.net/20.500.11850/152030.

MLA Handbook (7^th Edition):

Scholz, Ingo Gerhard. “Operator-based floquet theory and its applications to solid-state NMR.” 2010. Web. 05 Mar 2021.

Vancouver:

Scholz IG. Operator-based floquet theory and its applications to solid-state NMR. [Internet] [Doctoral dissertation]. ETH Zürich; 2010. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/20.500.11850/152030.

Council of Science Editors:

Scholz IG. Operator-based floquet theory and its applications to solid-state NMR. [Doctoral Dissertation]. ETH Zürich; 2010. Available from: http://hdl.handle.net/20.500.11850/152030

ETH Zürich

12. Tan, Kong Ooi. Pulse-Sequence Design in Solid-State NMR Using Floquet Theory.

Degree: 2016, ETH Zürich

URL: http://hdl.handle.net/20.500.11850/118186

Subjects/Keywords: FLOQUET THEORY (MATHEMATICAL ANALYSIS); FLOQUETTHEORIE (ANALYSIS); HAMILTON OPERATOR (QUANTUM THEORY); NUMERISCHE SIMULATION UND MATHEMATISCHE MODELLRECHNUNG; NUMERICAL SIMULATION AND MATHEMATICAL MODELING; SPIN DYNAMICS + SPIN ROTATION (CONDENSED MATTER PHYSICS); FESTKÖRPER-KERNRESONANZSPEKTROSKOPIE; SPINDYNAMIK + SPINROTATION (PHYSIK DER KONDENSIERTEN MATERIE); SOLID-STATE NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; HAMILTONOPERATOR (QUANTENTHEORIE); info:eu-repo/classification/ddc/530; Physics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Tan, K. O. (2016). Pulse-Sequence Design in Solid-State NMR Using Floquet Theory. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/118186

Chicago Manual of Style (16^th Edition):

Tan, Kong Ooi. “Pulse-Sequence Design in Solid-State NMR Using Floquet Theory.” 2016. Doctoral Dissertation, ETH Zürich. Accessed March 05, 2021. http://hdl.handle.net/20.500.11850/118186.

MLA Handbook (7^th Edition):

Tan, Kong Ooi. “Pulse-Sequence Design in Solid-State NMR Using Floquet Theory.” 2016. Web. 05 Mar 2021.

Vancouver:

Tan KO. Pulse-Sequence Design in Solid-State NMR Using Floquet Theory. [Internet] [Doctoral dissertation]. ETH Zürich; 2016. [cited 2021 Mar 05]. Available from: http://hdl.handle.net/20.500.11850/118186.

Council of Science Editors:

Tan KO. Pulse-Sequence Design in Solid-State NMR Using Floquet Theory. [Doctoral Dissertation]. ETH Zürich; 2016. Available from: http://hdl.handle.net/20.500.11850/118186

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