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... options exist: the traction from every fluid node on the interface is transferred to the corresponding solid node and the mid-nodes are ignored, which satisfies a global conservation of forces, or the traction from the fluid nodes are redistributed to every solid node, which locally is consistent with the finite element method. For the latter approach, and referring to Figure 3 which shows the traction imposed on an arbitrary solid edge along the FSI interface, the consistent FEM nodal loads are given by: ...
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Recently, a stabilizer free weak Galerkin (SFWG) method is proposed in [14], which is easier to implement and more efficient. In this paper, we developed an SFWG scheme for solving the general second-order elliptic problem on triangular meshes in 2D. This new SFWG method will dramatically reduce the error between the L²-projection of the exact solu...
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... Their method is based on a full Eulerian fluid-(bulk) structure coupling solver previously developed by Sugiyama et al. (2011), with the bulk structure replaced by elastic membranes. Suliman et al. (2015) presented a fully-coupled partitioned finite volume-finite volume and hybrid finite volume-finite element fluid-structure interaction scheme. In this scheme the fluid domain is modelled as a viscous incompressible isothermal region governed by the Navier-Stokes equations and discretised using an edge-based hybrid-unstructured vertex-centred finite volume methodology. ...
A monolithic mathematical framework for understanding the fluid-rigid-elastic structure interaction problem is proposed. A numerical method in a secondary formulation of the Navier-Stokes equations accompanying a technique for imposing the rigid boundaries is applied. The one-fluid formulation of the incompressible Navier-stokes equation, containing the terms governing the elastic structure, is transformed into the vorticity-stream function formulation. The rigid structure is imposed in the flow field based on the velocity-vorticity kinematic relation and harmonic function theorem. The vorticity, level-set function, and left Cauchy-Green deformation tensor are updated utilizing three transport equations to investigate the evolution of the velocity field, elastic structure(s) configuration, and elastic stress tensor. The method is implemented to solve three challenging problems, and the results show its capabilities in proper imposing the rigid structures in the flow field and also the simultaneous modeling the rigid and elastic structure interactions with incompressible fluid flow.
... All the smoothing procedures can be used to update the ALE grid. However, some of them are often found in the literature like the interpolation method used in [Suliman et al., 2015], [Song et al., 2013] where the displacements or velocities inside the mesh could be simply found by means of interpolations. Other mesh regularisation method are based on the Poisson equation resolution upon the coordinates or velocities initially proposed by [Winslow, 1963]. ...
Ces travaux visent à améliorer la biofidélité des modèles virtuels de l’être Humain. Les statistiques montrent que la tête humaine est fréquemment sujette à des traumatismes cérébraux, des lésions et autres blessures. Une attention particulière sera donc donnée à la modélisation de la tête. Afin de mieux prédire les mécanismes lésionnels de la tête, la biofidélite des modèles doit être améliorée, pour cela les effets du fluide situé à l’intérieur de la tête doivent être pris en compte. Cependant, la modélisation des interactions entre un fluide corporel visqueux et un matériau mou comme le cerveau reste un verrou scientifique. Il est proposé d’étudier en détail la modélisation des interactions fluide-structure entre un fluide et un corps mou. Premièrement, une étude bibliographique détaillée sur les méthodes numériques de modélisation des interactions fluides-structure a permis d’évaluer chacune d’elles et de juger de celle qui est la mieux adaptée pour la résolution de la problématique. Deuxièmement, lors de travaux de thèse précédents, une expérience a été réalisée montrant l’influence du liquide cérébrospinal sur la cinématique du cerveau lors d’un chargement dynamique. Cette expérience est utilisée dans un premier temps pour caractériser numériquement le gel silicone Sylgard 527 utilisé comme substitut de cerveau. Dans un second temps des méthodes de couplage partitionné disponible dans le code commercial LS-Dyna ICFD sont utilisées pour modéliser l’expérience. Bien que les modèles de gel précédemment caractérisés ont été utilisés, la version avec fluide n’a pas pu être modélisée avec succès. Troisièmement, un code de couplage partitionné est donc développé. Il consiste en un middleware écrit en C++ couplant deux codes éprouvés, OpenFOAM et LS-Dyna pour la modélisation du fluide et du solide respectivement. De plus, parce que très peu d’essais expérimentaux utilisables pour la validation de code d’interaction fluide-structure sont disponibles dans la littérature, une expérience permettant cela a été réalisée dans une soufflerie. La comparaison des prédictions numériques avec les résultats expérimentaux est prometteuse et donne des résultats globaux satisfaisants. Les points qui ne peuvent pas être validés nécessitent de plus amples investigations et permettront d’améliorer les techniques de modélisations et le développement du code.
... Although any formulation in deformed or undeformed configuration which considered the nonlinearities are theoretically equivalent, however, in solid mechanics, the application of formulas in updated mesh configurations is not optimal and the total Lagrangian form is more common. Suliman et al. (2010) applied FVM in this form for the analysis of large nonlinear deformation of solid structures and later they coupled it with a FVM fluid solver in a partitioned way (Suliman et al., 2015) to simulate the large nonlinear deformation of thin-walled structures interacting with incompressible fluid flows. Meanwhile, the analysis of the large nonlinear deformation of thin-walled structures interacting with compressible transonic flows has not been performed in the literature and it seems to be an important issue. ...
... Alternatively, the strong (implicit) coupling can be adopted [53,54,55], which has benefits in terms of stability and is comparable with a monolithic coupling. In this algorithm, the time step loop is equipped with an additional inner loop called "stage", thus if the "stage loop" converges the monolithic solutions is obtained. ...
This research work evaluates the performance of a Fluid Structure Interaction (FSI) solver, which is created using a generic interface to couple two independent software packages. The basic idea is to combine the advantages of the two independent codes to create a powerful FSI solver for two and three dimensional FSI analysis using the concept of modular programming. A detailed description about the implementation of an interface to couple a three-field system involved in the analysis is given, and this developed interface can be generalized to others codes. Since solving complex FSI problems is very time consuming, the focus of this work is placed on the performance of the coupled solver, for which a FSI benchmark will be solved on a computer cluster in order to measure speed up and efficiency.
A single screw extruder is used in this study to efficiently transport SiC slurry in direct ink writing (DIW) technology. The deposits caused by low viscosity and the agglomerations resulting from the nonuniform mixing form the obstacles in the channel, which affect the normal flow of the slurry, theoretical outlet velocity, and interaction with other printing parameters. Therefore, it is necessary to study the effect mechanism of the obstacles on the flow. The obstacles are always irregular, which makes it difficult to directly analyze them. Irregular geometries are always composed of linear and/or arcuate elements; therefore, the obstacles can be simplified into regular geometries. In the present work, interactive elements, including line-line, line-arc, arc-arc situations are analyzed. Then, an improved multiple relaxation time lattice Boltzmann method (MRT LBM) with a pseudo external force is proposed for the flow analysis. The improved MRT LBM is combined with rheological test data to investigate cases with interactive elements, and the results are applied to reveal the general mechanism. The results show that the positions are common influencing factors, which affect the streamlines, outflow directions, and outlet velocity distributions. In addition, in different situations, different factors are considered to affect SiC slurry flow. It is obvious that the existed obstacles inevitably change the theoretical flow direction and outlet velocity, which has a synergistic effect on the printing parameters. It is necessary to understand the effect mechanism of the obstacles on the flow.
The deformation of slender elastic structures due to the motion of surrounding fluid is a common multiphysics problem encountered in many applications. In this work we detail the development of a numerical model capable of solving such strongly-coupled fluid-structure interaction problems, and analyse the dynamic behaviour of multiple interacting bodies under fluid loading. In most fluid-structure interaction problems the deformation of slender elastic bodies is significant and cannot be described by a purely linear analysis. We present a new formulation to model these larger displacements. By extending the standard modal analysis technique for linear structural analysis, the governing equations and boundary conditions are updated to account for non-linear terms and a new modal formulation with quadratic modes is derived. The quadratic modal approach is tested on standard benchmark problems of increasing complexity and compared with analytical and full non-linear numerical solutions. An analysis of the dynamic interactions between multiple finite plates in various configurations under fluid loading, as well as the effects of the spacing between the structures, is also conducted. Numerical results are compared with theoretical and experimental approaches. The inverted hydrodynamic drafting effect of elastic bodies in an in-line configuration can be confirmed from our numerical simulations.
This research work evaluates the performance of a Fluid-Structure Interaction (FSI) solver, which is created using a generic interface to couple two independent software packages. The basic idea is to combine the advantages of the two independent codes to create a powerful FSI solver for two and three dimensional FSI analysis using the concept of modular programming. A detailed description about the implementation of an interface to couple a three-field system involved in the analysis is given, and this developed interface can be generalized to others codes. Since solving complex FSI problems is very time consuming, the focus of this work is placed on the performance of the coupled solver, for which a FSI benchmark will be solved on a computer cluster in order to measure speed up and efficiency.
