Development of Parallel Strongly Coupled Hybrid Fluid-structure Interaction Technology Involving Thin Geometrically Non-linear Structures PDF Download
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Author: Ridhwaan Suliman
Publisher:
ISBN:
Category : Fluid-structure interaction
Languages : en
Pages : 100
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Book Description
This work details the development of a computational tool that can accurately model strongly-coupled fluid-structure-interaction (FSI) problems, with a particular focus on thin-walled structures undergoing large, geometrically non-linear deformations, which has a major interest in, amongst others, the aerospace and biomedical industries. The first part of this work investigates improving the efficiency with which a stable and robust in-house code, Elemental, models thin structures undergoing dynamic fluid-induced bending deformations. Variations of the existing finite volume formulation as well as linear and higher-order finite element formulations are implemented. The governing equations for the solid domain are formulated in a total Lagrangian or undeformed conguration and large geometrically non-linear deformations are accounted for. The set of equations is solved via a single-step Jacobi iterative scheme which is implemented such as to ensure a matrix-free and robust solution. Second-order accurate temporal discretisation is achieved via dual-timestepping, with both consistent and lumped mass matrices and with a Jacobi pseudo-time iteration method employed for solution purposes. The matrix-free approach makes the scheme particularly well-suited for distributed memory parallel hardware architectures. Three key outcomes, not well documented in literature, are highlighted: the issue of shear locking or sensitivity to element aspect ratio, which is a common problem with the linear Q4 finite element formulation when subjected to bending, is evaluated on the finite volume formulations: a rigorous comparison of finite element vs. finite volume methods on geometrically non-linear structures is done: a higher-order finite volume solid mechanics procedure is developed and evaluated. The second part of this work is concerned with fluid-structure interaction (FSI) modelling. It considers the implementation and coupling of a higher order finite element structural solver with the existing finite volume fluid-flow solver in Elemental. To the author's knowledge, this is the first instance in which a strongly-coupled hybrid finite element finite volume FSI formulation is developed. The coupling between the fluid and structural components with non-matching nodes is rigorously assessed. A new partitioned fluid-solid interface coupling methodology is also developed, which ensures stable partitioned solution for strongly-coupled problems without any additional computational overhead. The solver is parallelised for distributed memory parallel hardware architectures. The developed technology is successfully validated through rigorous temporal and mesh independent studies of representative two-dimensional strongly-coupled large-displacement FSI test problems for which analytical or benchmark solutions exist.
Author: Ridhwaan Suliman
Publisher:
ISBN:
Category : Fluid-structure interaction
Languages : en
Pages : 100
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Book Description
This work details the development of a computational tool that can accurately model strongly-coupled fluid-structure-interaction (FSI) problems, with a particular focus on thin-walled structures undergoing large, geometrically non-linear deformations, which has a major interest in, amongst others, the aerospace and biomedical industries. The first part of this work investigates improving the efficiency with which a stable and robust in-house code, Elemental, models thin structures undergoing dynamic fluid-induced bending deformations. Variations of the existing finite volume formulation as well as linear and higher-order finite element formulations are implemented. The governing equations for the solid domain are formulated in a total Lagrangian or undeformed conguration and large geometrically non-linear deformations are accounted for. The set of equations is solved via a single-step Jacobi iterative scheme which is implemented such as to ensure a matrix-free and robust solution. Second-order accurate temporal discretisation is achieved via dual-timestepping, with both consistent and lumped mass matrices and with a Jacobi pseudo-time iteration method employed for solution purposes. The matrix-free approach makes the scheme particularly well-suited for distributed memory parallel hardware architectures. Three key outcomes, not well documented in literature, are highlighted: the issue of shear locking or sensitivity to element aspect ratio, which is a common problem with the linear Q4 finite element formulation when subjected to bending, is evaluated on the finite volume formulations: a rigorous comparison of finite element vs. finite volume methods on geometrically non-linear structures is done: a higher-order finite volume solid mechanics procedure is developed and evaluated. The second part of this work is concerned with fluid-structure interaction (FSI) modelling. It considers the implementation and coupling of a higher order finite element structural solver with the existing finite volume fluid-flow solver in Elemental. To the author's knowledge, this is the first instance in which a strongly-coupled hybrid finite element finite volume FSI formulation is developed. The coupling between the fluid and structural components with non-matching nodes is rigorously assessed. A new partitioned fluid-solid interface coupling methodology is also developed, which ensures stable partitioned solution for strongly-coupled problems without any additional computational overhead. The solver is parallelised for distributed memory parallel hardware architectures. The developed technology is successfully validated through rigorous temporal and mesh independent studies of representative two-dimensional strongly-coupled large-displacement FSI test problems for which analytical or benchmark solutions exist.
Author: Christophe Kassiotis
Publisher:
ISBN: 9782110987228
Category :
Languages : en
Pages : 153
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Book Description
Author: Avram Lev Robinson-Mosher
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
In this dissertation we consider the problem of simulating the interaction of fluids and structures. We present a strongly coupled (monolithic) fluid structure interaction framework for incompressible fluid flow using a fictitious domain approach to allow non-aligned fluid and structure meshes. We define boundary conditions between the domains and solve a coupled linear system for the impulse transfers which enforce them as well as the incompressibility condition for the fluid and the damping terms for the structure. We first present a symmetric, albeit indefinite linear system which satisfies these requirements and is stable for large time steps, high fluid/structure density ratios, and stiff constitutive models. The resulting method considers only the surface properties of the structure in the coupling and is therefore able to handle a wide range of constitutive models along with both thin and volumetric structures. We then demonstrate that by factoring the structure damping matrix we can obtain a symmetric and positive definite (SPD) coupled system. A fully converged solution to the new system is identical to that of the indefinite system and the SPD system can be solved via the conjugate gradient method and is easier to analyze and implement preconditioners for. The factoring technique is quite general and can be applied to the systems resulting from most dissipative forces, which we demonstrate for fluid viscosity (including Stokes flow) and intra-structure constraints. Finally, while no-slip boundary conditions are physical in most cases, often one does not have the luxury of a fully resolved simulation mesh and thus no-slip boundary conditions can result in nonphysically large boundary layers. We address this by considering extensions of the coupling scheme to slip boundary conditions.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 704
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Book Description
Author: Stefan Hartmann
Publisher: kassel university press GmbH
ISBN: 3899586670
Category :
Languages : en
Pages : 278
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Book Description
Author: Haym Benaroya
Publisher: Springer Science & Business Media
ISBN: 9400709951
Category : Technology & Engineering
Languages : en
Pages : 516
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Book Description
This plenary paper and the accompanying presentation have highlighted field problems involving fluid-structure interaction over a wide span of Navy operations. Considering the vast size and versatility of the Navy's inventory, the cases presented represent examples of a much larger problem. But even this limited set provides sufficient evidence that fluid-structure interaction does hinder the Navy's ability to accomplish its missions. This survey has also established that there are no accurate and generally applicable design tools for addressing these problems. In the majority of cases the state-of-practice is to either make ad-hoc adjustments and estimates based on historical evidence, or conduct expensive focused tests directed at each specific problem and/or candidate solution. Unfortunately, these approaches do not provide insight into the fundamental problem, and neither can be considered reliable regarding their likelihood of success. So the opportunities for applying computational fluid-structure interaction modeling to Navy problems appear limitless. Scenarios range from the "simple" resonant strumming of underwater and in-air cables, to the "self-contained" flow field and vibration of aircraft/ordnance bodies at various Mach numbers, to violent underwater transient detonations and local hull structural collapse. Generally applicable and computationally tractable design-oriented models for these phenomena are of course still far in the future. But the Navy has taken the first steps in that direction by sponsoring specialized numerical models, validation experiments tailored for specific applications, and conferences such as this one.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 992
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Book Description
Author: Marianna Braza
Publisher: Springer
ISBN: 3319273868
Category : Technology & Engineering
Languages : en
Pages : 358
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Book Description
This book addresses flow separation within the context of fluid-structure interaction phenomena. Here, new findings from two research communities focusing on fluids and structures are brought together, emphasizing the importance of a unified multidisciplinary approach. The book covers the theory, experimental findings, numerical simulations, and modeling in fluid dynamics and structural mechanics for both incompressible and compressible separated unsteady flows. There is a focus on the morphing of lifting structures in order to increase their aerodynamic and/or hydrodynamic performances, to control separation and to reduce noise, as well as to inspire the design of novel structures. The different chapters are based on contributions presented at the ERCOFTAC Symposium on Unsteady Separation in Fluid-Structure Interaction held in Mykonos, Greece, 17-21 June, 2013 and include extended discussions and new highlights. The book is intended for students, researchers and practitioners in the broad field of computational fluid dynamics and computational structural mechanics. It aims at supporting them while dealing with practical issues, such as developing control strategies for unsteady separation and applying smart materials and biomimetic approaches for design and control.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 11
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Book Description
Two- and three-dimensional fluid-structure interaction computer programs for the simulation of nonlinear dynamics were developed and applied to a number of problems. The programs were created by coupling Arbitrary Lagrangian-Eulerian finite volume fluid dynamics programs with strictly Lagrangian finite element structural dynamics programs. The resulting coupled programs can use either fully explicit or implicit time integration. The implicit time integration is accomplished by iterations of the fluid dynamics pressure solver and the structural dynamics system solver. The coupled programs have been used to solve problems involving incompressible fluids, membrane and shell elements, compressible multiphase flows, explosions in both air and water, and large displacements. In this paper, we present the approach used for the coupling and describe test problems that verify the two-dimensional programs against an experiment and an analytical linear problem. The experiment involves an explosion underwater near an instrumented thin steel plate. The analytical linear problem is the vibration of an infinite cylinder surrounded by an incompressible fluid to a given radius.
Author: Quentin Akkaoui
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
In 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.
