Дисертації з теми "Computational fluid-structure interactions"
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Pitman, Mark William. "An investigation of flow structure interactions on a finite compliant surface using computational methods." Thesis, Curtin University, 2007. http://hdl.handle.net/20.500.11937/625.
Повний текст джерелаPitman, Mark William. "An investigation of flow structure interactions on a finite compliant surface using computational methods." Curtin University of Technology, Department of Mechanical Engineering, 2007. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=17209.
Повний текст джерелаTwo numerical modelling techniques are adopted to approach the analysis of the FSI system. A potential-flow method is used for the modelling of flows in the limit of infinite Reynolds numbers, while a grid-free Discrete Vortex Method (DVM) is used for the modelling of the rotational boundary-layer flow at moderate Reynolds numbers. In both inviscid and viscous studies, significant contributions are made to the numerical modelling techniques. The application of these methods to the study of flow over compliant panels gives new insight to the nature of the FSI system. In the linear inviscid model, a novel hybrid computational/theoretical method is developed that evaluates the eigenvalues and eigenmodes from a discretised FSI system. The results from the non-linear inviscid model revealed that the steady-state of the non-linear wall motion is independent of initial excitation. For the viscous case, the first application of a DVM to model the interaction of a viscous, rotational flow with a compliant surface is developed. This DVM is successfully applied to model boundary-layer flow over a finite compliant surface.
Sheer, Francis Joseph. "Multi-Scale Computational Modeling of Fluid-Structure Interactions and Adhesion Dynamics in the Upper Respiratory System." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1316287639.
Повний текст джерелаLi, Yuwei. "Coupled computational fluid dynamics/multibody dynamics method with application to wind turbine simulations." Diss., University of Iowa, 2014. https://ir.uiowa.edu/etd/4681.
Повний текст джерелаConger, Michael Anthony. "Validation of CFD-MBD FSI for high-gidelity simulations of full-scale WAM-V sea-trials with suspended payload." Thesis, University of Iowa, 2015. https://ir.uiowa.edu/etd/1960.
Повний текст джерелаDombre, Emmanuel. "Modélisation non-linéaire des interactions vague-structure appliquée à des flotteurs d'éoliennes off-shore." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1050/document.
Повний текст джерелаThis PhD work is devoted to the study of nonlinear interactions between waves and floating rigid structures. The developed model relies on a boundary element method which reduces the dimensionality of the problem by one. First, a 2D model is applied to basic geometries and allows us to demonstrate the validity of the method for predicting the motion of a floating structrure subject to incoming monochromatic regular waves. Secondly, getting inspired by the 3D fully nonlinear potential flow model of Grilli textit{et al.}~cite{grilli2001fully}, we propose a novel model which generalizes the method for unstructured triangular meshes of 3D surfaces. The proposed model is able to deal with arbitrary configurations of multiple vertical cylinders interacting with the waves. We present academic validation test cases which show how the model works and behaves. Finally, we study situations of interest for EDF R&D related to floating off-shore wind turbines. A semi-submersible platform is evaluated with the nonlinear model
Vaterlaus, Austin C. "Development of a 3D Computational Vocal Fold Model Optimization Tool." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8468.
Повний текст джерелаKessy, Edgard. "Décomposition de domaine et calcul parallèle distribué : application à la mécanique des fluides." Rouen, 1997. http://www.theses.fr/1997ROUES052.
Повний текст джерелаPaton, Jonathan. "Computational fluid dynamics and fluid structure interaction of yacht sails." Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/14036/.
Повний текст джерелаYang, Liang. "An immersed computational framework for multiphase fluid-structure interaction." Thesis, Swansea University, 2015. https://cronfa.swan.ac.uk/Record/cronfa42413.
Повний текст джерелаYeh, Han Hung. "Computational analysis of fluid structure interaction in artificial heart valves." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44921.
Повний текст джерелаHafezi, Farzaneh. "Computational modelling of fluid-structure interaction at nano-scale boundaries." Thesis, Swansea University, 2014. https://cronfa.swan.ac.uk/Record/cronfa42753.
Повний текст джерелаBehrndtz, Frandsen Jannette. "Computational fluid structure interaction applied to long-span bridge design." Thesis, University of Cambridge, 1999. https://www.repository.cam.ac.uk/handle/1810/272004.
Повний текст джерелаCai, Shang-Gui. "Computational fluid-structure interaction with the moving immersed boundary method." Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2276/document.
Повний текст джерелаIn this thesis a novel non-body conforming mesh formulation is developed, called the moving immersed boundary method (MIBM), for the numerical simulation of fluid-structure interaction (FSI). The primary goal is to enable solids of complex shape to move arbitrarily in an incompressible viscous fluid, without fitting the solid boundary motion with dynamic meshes. This novel method enforces the no-slip boundary condition exactly at the fluid-solid interface with a boundary force, without introducing any artificial constants to the rigid body formulation. As a result, large time step can be used in current method. To determine the boundary force more efficiently in case of moving boundaries, an additional moving force equation is derived and the resulting system is solved by the conjugate gradient method. The proposed method is highly portable and can be integrated into any fluid solver as a plug-in. In the present thesis, the MIBM is implemented in the fluid solver based on the projection method. In order to obtain results of high accuracy, the rotational incremental pressure correction projection method is adopted, which is free of numerical boundary layer and is second order accurate. To accelerate the calculation of the pressure Poisson equation, the multi-grid method is employed as a preconditioner together with the conjugate gradient method as a solver. The code is further parallelized on the graphics processing unit (GPU) with the CUDA library to enjoy high performance computing. At last, the proposed MIBM is applied to the study of two-way FSI problem. For stability and modularity reasons, a partitioned implicit scheme is selected for this strongly coupled problem. The interface matching of fluid and solid variables is realized through a fixed point iteration. To reduce the computational cost, a novel efficient coupling scheme is proposed by removing the time-consuming pressure Poisson equation from this fixed point interaction. The proposed method has shown a promising performance in modeling complex FSI system
Kapor, Jarrad Stephen. "Novel computational methods for the study of compliant-wall fluid-structure interaction." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/819.
Повний текст джерелаNagai, Toshiki. "Space-time Extended Finite Element Method with Applications to Fluid-structure Interaction Problems." Thesis, University of Colorado at Boulder, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10844711.
Повний текст джерелаThis thesis presents a space-time extended finite element method (space-time XFEM) based on the Heaviside enrichment for transient problems with moving interfaces, and its applications to the fluid-structure interaction (FSI) analysis. The Heaviside-enriched XFEM is a promising method to discretize partial differential equations with discontinuities in space. However, significant approximation errors are introduced by time stepping schemes when the interface geometry changes in time. The proposed space-time XFEM applies the finite element discretization and the Heaviside enrichment in both space and time with elements forming a space-time slab. A simple space-time scheme is introduced to integrate the weak form of the governing equations. This scheme considers spatial intersection configuration at multiple temporal integration points. Standard spatial integration techniques can be applied for each spatial configuration. Nitsche's method and the face-oriented ghost-penalty method are extended to the proposed space-time XFEM formulation. The stability, accuracy and flexibility of the space-time XFEM for various interface conditions including moving interfaces are demonstrated with structural and fluid problems. Moreover, the space-time XFEM enables analyzing complex FSI problems using moving interfaces, such as FSI with contact. Two FSI methods using moving interfaces (full-Eulerian FSI and Lagrangian-immersed FSI) are studied. The Lagrangian-immersed FSI method is a mixed formulation of Lagrangian and Eulerian descriptions. As solid and fluid meshes are independently defined, the FSI is computed between non-matching interfaces based on Nitsche's method and projection techniques adopted from computational contact mechanics. The stabilized Lagrange multiplier method is used for contact. Numerical examples of FSI and FSI-contact problems provide insight into the characteristics of the combination of the space-time XFEM and the Lagrangian-immersed FSI method. The proposed combination is a promising method which has the versatility for various multi-physics simulations and the applicability such as optimization.
Miller, Samuel C. "Fluid-Structure Interaction of a Variable Camber Compliant Wing." University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1428575972.
Повний текст джерелаScroggs, Richard A. "Validation of computational fluid-structure interaction models by comparison with collapsible tube experiments." Thesis, University of Sheffield, 2002. http://etheses.whiterose.ac.uk/14835/.
Повний текст джерелаMohnot, Anshul. "Solution of fluid-structure interaction problems using a discontinuous Galerkin technique." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43798.
Повний текст джерелаIncludes bibliographical references (p. 57-58).
The present work aims to address the problem of fluid-structure interaction using a discontinuous Galerkin approach. Starting from the Navier-Stokes equations on a fixed domain, an arbitrary Lagrangian Eulerian (ALE) approach is used to derive the equations for the deforming domain. A geometric conservation law (GCL) is then introduced, which guarantees freestream preservation of the numerical scheme. The space discretization is performed using a discontinuous Galerkin method and time integration is performed using either an explicit four stage Runge-Kutta scheme or an implicit BDF2 scheme. The mapping parameters for the ALE formulation are then obtained using algorithms based on radial basis functions (RBF) or linear elasticity. These strategies are robust and can be applied to bodies with arbitrary shapes and undergoing arbitrary motions. The robustness and accuracy of the ALE scheme coupled with these mapping strategies is then demonstrated by solving some model problems. The ability of the scheme to handle complex flow problems is demonstrated by analyzing the low Reynolds number flow over an oscillating circular cylinder.
by Anshul Mohnot.
S.M.
Nave, Jr Gary Kirk. "Nonlinear Models and Geometric Structure of Fluid Forcing on Moving Bodies." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/84945.
Повний текст джерелаPh. D.
Pouplana, I. de (Ignasi de). "Development of new computational methods for fluid-structure interaction analysis of multi-fractured media." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/461413.
Повний текст джерелаEl objetivo de esta tesis es la derivación e implementación de una formulación robusta de Elementos Finitos para la solución de problemas acoplados de sólido-fluido de poro en medios porosos multi-fracturados. Una formulación del MEF acoplada desplazamiento-presión de poro para resolver problemas de interacción solido-fluido de poro es primeramente introducida. La interacción entre ambos componentes es gobernada por dos ecuaciones: el balance de momento para la mezcla sólido-fluido y el balance de masa para el fluido de poro. Bajo condiciones de impermeabilidad e incompresibilidad, esta formulación sufre problemas de inestabilidad debido a la violación de las condiciones Babuska-Brezzi. Para poder trabajar con elementos de igual orden de interpolación para los desplazamientos y la presión de poro, la formulación es estabilizada mediante el método de Finite Increment Calculus (FIC). La formulación estabilizada con FIC es testeada contra elementos estables de mayor orden de interpolación para el campo de desplazamientos en ejemplos 2D y 3D. La mecánica del daño continua es la base de la estrategia de crecimiento de fisura para la técnica de propagación de fracturas propuesta. Los modelos de deformación con reblandecimiento utilizados para materiales cuasi-frágiles favorecen la localización espuria de las deformaciones y el mal condicionamiento del problema de valores en el contorno si la variable de daño depende únicamente del estado de deformación en el punto considerado. Un modelo de daño no-local de tipo integral asociado a un parámetro de longitud característica es presentado como un método para controlar el tamaño de la zona de fractura y regularizar totalmente el problema. Dos ejemplos son resueltos para evaluar la robustez del modelo frente a cambios en la discretización espacial. Elementos de interface de espesor cuasi-cero son formulados para representar discontinuidades en el dominio poroso. Un modelo de fractura cohesiva bilineal es utilizado para describir su comportamiento mecánico, y una formulación derivada de la ley cúbica modela el flujo de fluido a través de la fisura. Finalmente, una nueva metodología para la simulación de procesos de propagación de fractura en medios porosos saturados es presentada. El modelo de daño no-local es empleado juntamente con los elementos de interface para predecir el mapa de degradación del dominio e insertar nuevas fracturas seguido de un remallado. Ejemplos de fractura por fluido en 2D y 3D son presentados para ilustrar la precisión de la técnica propuesta.
Chun, Sangeon. "Nonlinear Fluid-Structure Interaction in a Flexible Shelter under Blast Loading." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/29849.
Повний текст джерелаPh. D.
Byrd, Alex W. "Fluid-Structure Interaction Simulations of a Flapping Wing Micro Air Vehicle." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401559891.
Повний текст джерелаQuintero, Igeño Pedro Manuel. "Characterization of Fluid Structure Interaction mechanisms and its application to vibroacoustic phenomena." Doctoral thesis, Universitat Politècnica de València, 2019. http://hdl.handle.net/10251/128412.
Повний текст джерела[CAT] La Interacció Fluid Estructura consisteix en un problema físic en què dos materials, governats per conjunts d'equacions diferents, s'acoblen de diferents formes. La investigació en el camp de la Interacció Fluid Esructura va experimentar un important desenvolupament des de principis del segle XX, de la mà del camp de la aeroelasticdad. Durant el desenvolupament de la indústria aeroespacial en el context de les guerres mundials, l'ús de materials més lleugers (i flexibles) va començar a fer-se obligatori per a l'obtenció d'aeronaus amb un comportament (i costos) acceptable. Al llarg dels últims anys, l'ús de materials de construcció cada vegada més lleugers, s'ha estès a la resta de camps de la indústria. A tall d'exemple, podria servir el desenvolupament de textit trackers en la producció d'energia solar; la utilització de materials lleugers en enginyeria civil, el desenvolupament d'elements constructius de plàstic a la indústria de l'automòbil. Com a conseqüència, la predicció amb exactitud de les deformacions induïdes per un fluid i, si escau, la influència d'aquestes deformacions en el propi flux, ha adquirit una importància vital. Aquest document intenta porporcionar, en primer lloc, una profunda revisió dels mètodes experimentals i computacionals que s'han utilitzat en aquest context en la bibliografia, així com les anàlisis en problemes d'aquest tipus realitzats per altres investigadors de cara a presentar una primera aproximació a la Interacció Fluid Estructura. Es veurà com, encara que existeix una important quantitat d'eines i metodologies aplicables a qualsevol tipus de problema i per a qualsevol combinació de fluxos i estructures, no hi ha una aproximació general que, en funció de valors de nombres adimensionals, permeti establir quins d'ells són els de major importància en aquest tipus de problemes. En aquest sentit, es durà a terme una completa anàlisi paramètric durant el desenvolupament del Capítol 2 per a establir quins d'ells són de major importància. Un cop s'estableixi la importància d'aquests paràmetres, s'analitzarà un cas que és d'especial interès en la indústria: la aerovibroacústica. Això és un cas particular d'Interacció Fluid Estructura en què, a causa de la combinació de paràmetres adimensionals, la interacció es pot considerar com pràcticament unidireccional, permetent estendre estudis mitjançant un consti computacional relativament acotat. La Aerovibroacústica i la vibroacústica s'analitzaran mitjançant la presentació de dos casos de referència, permetent proposar una metodologia que es podrà estendre a altres problemes similars.
[EN] Fluid Structure Interaction is a physical problem where two different materials, governed by different set of fundamental equation, are coupled on different ways. The research on the field of Fluid Structure Interaction experienced a noticeable growth since the beginnings of the XXth century, by means of the field of aeroelasticity. During the development of the aerospace industry in the context of first and second Wolrd War, as the use of lighter (and softer) materials became mandatory for the correct behavior (and cost savings) of the produced aircrafts. During these past years, the use of use of increasingly lighter construction materials has extended to the rest of fields of the industry. As an example, it could be mentioned the use of solar trackers on the solar energy sector; the use of light materials on civil engineering or the use of plastic for some constructive elements in the context of the automotive field. As a consequence, the accurate prediction of the deformations induced to a fluid flow over a structure and, if needed, the influence of this deformation on the fluid flow itself is becoming of primal importance. This document intends to provide with a deep review of the computational and experimental reported methodologies already available on the literature and the previous works performed by other researches in order to infer a first approximation to the Fluid Structure Interaction Problem. It will be observed how an important amount of solving methodologies is available in order to face these problems regarding with the strength of the interaction. However, a general approximation allowing to predict this strength as a function of a set of dimensional number is rarely known. In this sense, a full parametric study will be performed during the development of Chapter 2 showing which of them are of higher importance. Once the influence of these parameters is determined, a case of special interest will be analyzed: aerovibroacoustics. This, is a particular case of Fluid Structure Interaction where, due to the combination of its nondimensional parameters, one directional coupling can be supposed for most of the cases. Aerovibroacoustics and vibroacoustics will be analyzed by means of two reference cases, allowing finally to propose a methodology which could be extended for other related problems.
Quintero Igeño, PM. (2019). Characterization of Fluid Structure Interaction mechanisms and its application to vibroacoustic phenomena [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/128412
TESIS
Ramirez, Villalba Leidy catherine. "Towards an efficient modeling of Fluid-Structure Interaction." Thesis, Ecole centrale de Nantes, 2020. http://www.theses.fr/2020ECDN0029.
Повний текст джерелаFSI industrial applications are often described by complex geometries and materials. In order to accurately predict their behavior, high computational costs are associated, both in time and in computational resources. To improve the quality of the prediction without penalizing the computational time, and to reduce the computational time without impacting the accuracy that is available today, two main axes are explored in this work. The first one is the study of an asynchronous algorithm that could allow the use of complex structural models. The second axis consists of the study of the strip method while combining the use of a RANS model and a non-linear FEM model. On the one hand, the study of asynchronicity in the FSI domain revealed different aspects of interest that must be addressed before the approach can be used industrially. However, a first treatment of the limitations found showed signs of an improvement that could lead to a promising algorithm, one that naturally lies between the implicit external algorithm and the implicit internal algorithm. On the other hand, it was shown that the strip method developed in this work achieves a significant reduction in calculation time while maintaining excellent accuracy
Lemmon, Jack David Jr. "Three-dimensional computational modeling of fluid-structure interaction : study of diastolic function in a thin-walled left heart model." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/15912.
Повний текст джерелаMehra, Puneet. "Fluid-Structure Interaction Modeling of Human Upper Airway Collapse in Obstructive Sleep Apnea." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563873512457421.
Повний текст джерелаCole, Robert Edward. "Numerical Modeling of Air Cushion Vehicle Flexible Seals." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/83828.
Повний текст джерелаPh. D.
Heminger, Michael Alan. "Dynamic Grid Motion in a High-Order Computational Aeroacoustic Solver." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1272550725.
Повний текст джерелаGao, Hao. "Carotid plaque stress analysis by fluid structure interaction based on in-vivo MRI : implications to plaque vulnerability assessment." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4731.
Повний текст джерелаGao, Haotian. "POD-Galerkin based ROM for fluid flow with moving boundaries and the model adaptation in parametric space." Diss., Kansas State University, 2018. http://hdl.handle.net/2097/38776.
Повний текст джерелаDepartment of Mechanical and Nuclear Engineering
Mingjun Wei
In this study, a global Proper Orthogonal Decomposition (POD)-Galerkin based Reduced Order model (ROM) is proposed. It is extended from usual fixed-domain problems to more general fluid-solid systems with moving boundaries/interfaces. The idea of the extension is similar to the immersed boundary method in numerical simulations which uses embedded forcing terms to represent boundary motions and domain changes. This immersed boundary method allows a globally defined fixed domain including both fluid and solid, where POD-Galerkin projection can be directly applied. However, such a modified approach cannot get away with the unsteadiness of boundary terms which appear as time-dependent coefficients in the new Galerkin model. These coefficients need to be pre-computed for prescribed periodic motion, or worse, to be computed at each time step for non-prescribed (e.g. with fluid-structure interaction) or non-periodic situations. Though computational time for each unsteady coefficient is smaller than the coefficients in a typical Galerkin model, because the associated integration is only in the close neighborhood of moving boundaries. The time cost is still much higher than a typical Galerkin model with constant coefficients. This extra expense for moving-boundary treatment eventually undermines the value of using ROMs. An aggressive approach is to decompose the moving boundary/domain to orthogonal modes and derive another low-order model with fixed coefficients for boundary motion. With this domain decomposition, an approach including two coupled low-order models both with fixed coefficients is proposed. Therefore, the new global ROM with decomposed approach is more efficient. Though the model with the domain decomposition is less accurate at the boundary, it is a fair trade-off for the benefit on saving computational cost. The study further shows, however, that the most time-consuming integration in both approaches, which come from the unsteady motion, has almost negligible impact on the overall dynamics. Dropping these time-consuming terms reduces the computation cost by at least one order while having no obvious effect on model accuracy. Based on this global POD-Galerkin based ROM with forcing term, an improved ROM which can handle the parametric variation of body motions in a certain range is also presented. This study shows that these forcing terms not only represent the moving of the boundary, but also decouple the moving parameters from the computation of model coefficients. The decoupling of control parameters provides the convenience to adapt the model for the prediction on states under variation of control parameters. An improved ROM including a shit mode seems promising in model adaptation for typical problems in a fixed domain. However, the benefit from adding a shit mode to model diminishes when the method is applied to moving-boundary problems. Instead, a combined model, which integrates data from a different set of parameters to generate the POD modes, provides a stable and accurate ROM in a certain range of parametric space for moving-boundary problems. By introducing more data from a different set of parameters, the error of the new model can be further reduced. This shows that the combined model can be trained by introducing more and more information. With the idea of the combined model, the improved global ROM with forcing terms shows impressive capability to predict problems with different unknown moving parameters, and can be used in future parametric control and optimization problems.
Hägglund, Jesper. "Simulated cerebrospinal fluid motion due to pulsatile arterial flow : Master Thesis Project." Thesis, Umeå universitet, Institutionen för fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-182508.
Повний текст джерелаBenitez, Mendieta Jessica. "Patient-specific computational biomechanical analysis of carotid atherosclerotic plaques based on MRI." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/213840/1/Jessica_Benitez%20Mendieta_Thesis.pdf.
Повний текст джерелаNasar, Abouzied. "Eulerian and Lagrangian smoothed particle hydrodynamics as models for the interaction of fluids and flexible structures in biomedical flows." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/eulerian-and-lagrangian-smoothed-particle-hydrodynamics-as-models-for-the-interaction-of-fluids-and-flexible-structures-in-biomedical-flows(507cd0db-0116-4258-81f2-8d242e8984fa).html.
Повний текст джерелаWuilbaut, Thomas A. I. J. "Algorithmic developments for a multiphysics framework." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210407.
Повний текст джерелаflutter for linear elastic structures in compressible fl
ows, conjugate heat transfer for re-entry vehicles including thermo-chemical reactions and finally, industrial electro-chemical plating processes which often include
stiff source terms. These problems are often solved using specifically developed
solvers, but these cannot easily be reused for different purposes. We have therefore considered the development of a
flexible and reusable software platform for the simulation of multi-physics problems. We have based this
development on the COOLFluiD framework developed at the von Karman Institute in collaboration with a group of partner institutions.
For the solution of fl
uid fl
ow problems involving compressible
flows, we have used the Finite Volume method and we have focused on the application of the method to moving and deforming computational domains using the Arbitrary Lagrangian Eulerian formulation. Validation on a series of testcases (including turbulent flows) is shown. In parallel, novel time integration
methods have been derived from two popular time discretization methods.
They allow to reduce the computational effort needed for unsteady fl
ow computations.
Good numerical properties have been obtained for both methods.
For the computations on deforming domains, a series of mesh deformation techniques are described and compared. In particular, the effect of the stiffness definition is analyzed for the Solid material analogy technique. Using
the techniques developed, large movements can be obtained while preserving a good mesh quality. In order to account for very large movements for which mesh deformation techniques lead to badly behaved meshes, remeshing is also considered.
We also focus on the numerical discretization of a class of physical models that are often associated with
fluid fl
ows in coupled problems. For the elliptic problems considered here (elasticity, heat conduction and electrochemical
potential problems), the implementation of a Finite Element solver is presented. Standard techniques are described and applied for a variety of problems, both steady and unsteady.
Finally, we discuss the coupling of the
fluid flow solver with the finite element solver for a series of applications. We concentrate only on loosely and strongly coupled algorithms and the issues associated with their use and implementation. The treatment of non-conformal meshes at the interface between two coupled computational domains is discussed and the problem
of the conservation of global quantities is analyzed. The software development of a
flexible multi-physics framework is also detailed. Then, several coupling algorithms are described and assessed for testcases in aeroelasticity and conjugate heat transfer showing the integration of the
fluid and solid solvers within a multi-physics framework. A novel strongly coupled algorithm, based on a Jacobian-Free Newton-Krylov method is also presented and applied to stiff coupled electrochemical potential problems.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Dobes, Jiri. "Numerical algorithms for the computation of steady and unsteady compressible flow over moving geometries: application to fluid-structure interaction." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210640.
Повний текст джерелаThis work deals with the development of numerical methods for compressible flow simulation with application to the interaction of fluid flows and structural bodies.
First, we develop numerical methods based on multidimensional upwind residual distribution (RD) schemes. Theoretical results for the stability and accuracy of the methods are given. Then, the RD schemes for unsteady problems are extended for computations on moving meshes. As a second approach, cell centered and vertex centered finite volume (FV) schemes are considered. The RD schemes are compared to FV schemes by means of the 1D modified equation and by the comparison of the numerical results for scalar problems and system of Euler equations. We present a number of two and three dimensional steady and unsteady test cases, illustrating properties of the numerical methods. The results are compared with the theoretical solution and experimental data.
In the second part, a numerical method for fluid-structure interaction problems is developed. The problem is divided into three distinct sub-problems: Computational Fluid Dynamics, Computational Solid Mechanics and the problem of fluid mesh movement. The problem of Computational Solid Mechanics is formulated as a system of partial differential equations for an anisotropic elastic continuum and solved by the finite element method. The mesh movement is determined using the pseudo-elastic continuum approach and solved again by the finite element method. The coupling of the problems is achieved by a simple sub-iterative approach. Capabilities of the methods are demonstrated on computations of 2D supersonic panel flutter and 3D transonic flutter of the AGARD 445.6 wing. In the first case, the results are compared with the theoretical solution and the numerical computations given in the references. In the second case the comparison with experimental data is presented.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Kadel, Saurav. "Computational Assessment of Aortic Valve Function and Mechanics under Hypertension." Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1594243694736478.
Повний текст джерелаGoddard, Aaron M. "A primarily Eulerian means of applying left ventricle boundary conditions for the purpose of patient-specific heart valve modeling." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6584.
Повний текст джерелаAkkaoui, Quentin. "Computational dynamics of geometrically nonlinear structures coupled with acoustic fluids in presence of sloshing and capillarity : uncertainty quantification." Thesis, Paris Est, 2019. http://www.theses.fr/2019PESC2001.
Повний текст джерелаIn this thesis, we are interested in computationally modeling and simulating coupled fluid-structure systems constituted of an elastic structure partially filled with a fluid with a free surface, considering the effects of sloshing and capillarity. The internal fluid is linear, acoustic, dissipative, and the linear elastic structure is submitted to large displacements inducing geometrical nonlinearities. The work presented in this manuscript first details the theoretical study regarding such coupled fluid-structure systems and focuses on the construction and implementation of the computational model using an adapted nonlinear reduced-order model. This reduced-order model allows for performing the nonlinear dynamical simulations and for better understanding the phenomena related to each subset of the coupled system. Several numerical applications are then presented to analyze various phenomena related to the different coupling mechanisms and energy transfers in such fluid-structure system. The first development axis consists in quantifying and reducing the computational resources required for the construction of the projection basis of the reduced-order model when dealing with very-large dimension fluid-structure computational models. A new methodology is presented, which allows for reducing the computational costs required for solving three generalized eigenvalue problems that cannot be solved on medium-power computers. A second development axis is devoted to the quantification of the influence of the coupling operator between the structure and the free surface of the internal liquid allowing for taking into account the capillary contact angle condition on the triple line while considering a deformable structure. The third axis is based on experimental research published in 1962 in the framework of NASA researches for orbital launchers, which highlighted an unexpected phenomenon of large amplitude and low-frequency sloshing of an internal liquid for a medium-frequency excitation of the tank. We propose to revisit these experimental results and to explain the causes of such unexpected phenomenon through a numerical simulation taking into account the geometrical nonlinearities of the structure. Finally, the last development axis is devoted to the propagation of nonparametric uncertainties of the structure in the system by the different coupling mechanisms. The nonparametric stochastic model is the nonparametric probabilistic approach using the random matrix theory. A methodology for identifying the hyperparameter is presented, based on an experimental data set and on an inverse statistical problem. A numerical validation of this method on a simulated experimental data set is presented
Gardner, Kevin Alexander. "Experimental Study of Air Blast and Water Shock Loading on Automotive Body Panels." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468938824.
Повний текст джерелаVolpi, Silvia. "High-fidelity multidisciplinary design optimization of a 3D composite material hydrofoil." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6325.
Повний текст джерелаLu, Zhaokuan. "Computationally-effective Modeling of Far-field Underwater Explosion for Early-stage Surface Ship Design." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/104996.
Повний текст джерелаDoctor of Philosophy
The vulnerability of a ship to the impact of underwater explosions (UNDEX) and how to incorporate this factor into early-stage ship design is an important aspect in the ship survivability study. In this dissertation, attention is focused on the cost-efficient simulation of the ship response to a far-field UNDEX which involves fluid shock waves, cavitation, and fluid-structural interaction. Traditional fluid numerical simulation approaches using the Finite Element Method to track wave propagation and cavitation requires a highly refined mesh to deal with large numerical errors. Computation also becomes quite expensive for full ship-related problems due to the large fluid domain necessary to envelop the ship. The burden is aggravated by the need to generate a fluid mesh around the irregular ship hull geometry, which typically requires significant manual intervention. To accelerate the design process and enable the consideration of far-field UNDEX vulnerability, several contributions are made in this dissertation to make the simulation more efficient. First, a Cavitating Acoustic Spectral Element approach, which has shown computational advantages in UNDEX problems but not systematically assessed in total ship application, is used to model the fluid. The use of spectral elements shows greater structural response accuracy and lower computational cost than the traditional FEM. Second, a novel fully automatic all-hexahedral mesh generation scheme is applied to generate the fluid mesh. Along with the spectral element, the all-hex mesh shows greater accuracy than the all-tetrahedral finite element mesh which is typically used. A further contribution of this dissertation is the development of a non-numerical approach which can approximate peak structural responses comparable to the numerical solution with far less computational effort.
Muddle, Richard Louden. "Parallel block preconditioning for multi-physics problems." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/parallel-block-preconditioning-for-multiphysics-problems(2efc63e4-f426-4be9-b48a-4016365e08b8).html.
Повний текст джерелаAger, Christoph Franz [Verfasser], Wolfgang A. [Akademischer Betreuer] Wall, Wolfgang A. [Gutachter] Wall, and Marek [Gutachter] Behr. "Computational Methods for Fluid-Structure Interaction including Porous Media and Solid Contact / Christoph Franz Ager ; Gutachter: Wolfgang A. Wall, Marek Behr ; Betreuer: Wolfgang A. Wall." München : Universitätsbibliothek der TU München, 2021. http://d-nb.info/1230985131/34.
Повний текст джерелаAuza, Gutierrez Rodrigo. "Prediction of Aerodynamically Induced Hood Vibration of Trailing Vehicles." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1546472529004518.
Повний текст джерелаSubramaniam, Dhananjay Radhakrishnan. "Role of Elasticity in Respiratory and Cardiovascular Flow." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1522054562050044.
Повний текст джерелаTaraconat, Pierre. "Application of numerical simulation for a better characterization of red blood cells by impedance measurement." Thesis, Montpellier, 2020. http://www.theses.fr/2020MONTS006.
Повний текст джерелаIn Coulter counters, cells counting and volumetry is achieved by monitoring their electrical print when they flow through a polarized micro-orifice.However, the volume measurement may be impaired when the trajectory of the cell is in the vicinity of the aperture edges due to complex dynamics and deformations of the cell.In this thesis, numerical simulations of the dynamics and electrical signature of red blood cells (RBCs) in a Coulter counter are presented, accounting for the deformability of the cells.In particular, a specific numerical pipeline is developed to overcome the challenge of the multi-scale nature of the problem.It consists in segmenting the whole computation of the cell dynamics and electrical response in a series of dedicated computations, with a saving of one order of magnitude in computational time.This numerical pipeline is used with rigid spheres and deformable red blood cells in an industrial Coulter counter geometry and compared with experimental measurements.The simulations not only reproduce electrical signatures typical of those measured experimentally, but also provide an understanding of the key mechanisms at play in the complex signatures induced by RBCs following a near-wall trajectory.Based on this new understanding provided by numerical simulations, a filtering strategy is introduced, which allows the filtering of pulses induced by near-wall paths which are irrelevant for the cells sizing.The method is shown to retrieve the expected symmetrical distribution of RBCs and provides results comparable to hydrodynamical focusing, a more intricate implementation of the Coulter principle.Such a result paves the way for a robust assessment of haematological parameters with a cheaper and simpler implementation, compared to hydrofocused devices.The impact of the cell morphology and rheology on the electrical print is evidenced for near-wall trajectories.Indeed, by altering the cell deformability and sphericity, the electrical pulses are proven to differ from predefined normality of measurements.Furthermore, neural network modellings are performed in the aims of assessing such RBC properties.Among the proposed processing, classification of normal, stiffened and spherical RBCs is provided.Finally, the inverse problem of numerical simulations is achieved, thus allowing the evaluation of the mechanical parameters of RBCs
Sanches, Rodolfo André Kuche. "Análise bidimensional de interação fluido-estrutura: desenvolvimento de código computacional." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-06112006-145215/.
Повний текст джерелаThe present work consists of the development of a computational code based on the element finite method for fluid-structure interaction analysis. A two-dimensional fluid dynamic Eulerian code is developed based on the CBS algorithm characteristic based split. Then, the computational code is modified to be coupled with a Lagrangean structures dynamical code by using the arbitrary Lagrangean Eulerian description (ALE). At the end, the coupling is made with a positional nonlinear geometrical structural dynamics code based on the finite element method.
Acikgoz, Nazmiye. "Adaptive and Dynamic Meshing Methods for Numerical Simulations." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14521.
Повний текст джерелаBraun, Alexandre Luis. "Simulação numérica na engenharia do vento incluindo efeitos de interação fluido-estrutura." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2007. http://hdl.handle.net/10183/10592.
Повний текст джерелаAnalysis and development of numerical tools to simulate Computational Wind Engineering (CWE) problems is the main goal of the present work. The isothermal flow is analyzed using the Navier-Stokes equations for viscous fluids and a mass conservation equation obtained according to the pseudo-compressibility assumption. Turbulent flows are simulated employing Large Eddy Simulation (LES) with the classical and dynamic Smagorinsky’s models for subgrid scales. Two Taylor-Galerkin models for the flow analysis are investigated: the explicit two-step scheme and the explicit-iterative scheme. The Finite Element Method (MEF) is employed for spatial discretizations using the eight-node hexahedrical isoparametric element with one-point quadrature. Fluid-structure interaction problems are analyzed with a coupling model based on a conservative partitioned scheme. The Finite Element Method (MEF) is employed for spatial discretizations using the eight-node hexahedrical isoparametric element with one-point quadrature. Fluid-structure interaction problems are analyzed with a coupling model based on a conservative partitioned scheme. Subcycling and nonmatching meshes for independent discretizations of the fluid and structure domains are also available. The structure is considered as a deformable body constituted by a linear elastic material with geometrically nonlinear effects. The FEM is used for the spatial discretization of the structure as well. Eight-node hexahedrical isoparametric elements with one-point quadrature and hourglass control are adopted in this process. The implicit Newmark algorithm within the framework of the α-Generalized method is employed for the numerical integration of the dynamic equilibrium equation. An arbitrary Lagrangean-Eulerian (ALE) description is adopted for the kinematic description of the flow when deformable structures are analyzed. Numerical and experimental examples are simulated in order to demonstrate the accuracy of the developed algorithms. Concluding remarks and suggestions for future works are pointed out in the last chapter of the present work.