Bibliografías temáticas / Navier-Stokes equations. Numerical grid generation (Numerical analysis) Fluid-structure interaction

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Literatura académica sobre el tema "Navier-Stokes equations. Numerical grid generation (Numerical analysis) Fluid-structure interaction"

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Publicado: 4 de junio de 2021

Última modificación: 12 de febrero de 2022

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Artículos de revistas sobre el tema "Navier-Stokes equations. Numerical grid generation (Numerical analysis) Fluid-structure interaction"

Li, Xue Feng, Xiu Quan Huang y Chao Liu. "Numerical Simulation Method for Fluid-Structure Interaction in Compressor Blades". Applied Mechanics and Materials 488-489 (enero de 2014): 914–17. http://dx.doi.org/10.4028/www.scientific.net/amm.488-489.914.

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A simulation method for fluid-structure interaction (FSI) in compressor blades was discussed to predict the aeroelastic stability of blades. Using the MFX, which is a Multi-Field Solver in ANSYS, the total force of computational fluid dynamics (CFD) have been interpolated to computational structural dynamics (CSD) grids, and then the vibration displacements of CSD nodes have been interpolated to CFD grids at the blade surface. In CFD analysis, the grid coordinates of the moveable region have been updated by multi-layer moving grid technique, and the finite volume method has been applied to calculate the Reynolds-averaged Navier-Stokes (RANS) equations closed by k-E turbulent model. For NASA Rotor 67, detect the displacement response of compressor blades at the design speed , and the aeroelastic stability of blades has been analyzed preliminarily. The study shows that the FSI procedure is feasible to predict the aeroelastic stability of compressor blades.

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Han, Cheol Heui, Sang Jin Ma y Myung Jin Chung. "Effect of Flow Characteristics on the Operation of a Solenoid Switching Control Valve". Applied Mechanics and Materials 799-800 (octubre de 2015): 1113–16. http://dx.doi.org/10.4028/www.scientific.net/amm.799-800.1113.

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Effect of the compressible flow characteristics inside a high-speed electromagnetic valve on the operation of the valve is investigated using a numerical simulation. The numerical simulation solves Navier-Stokes equations and heat transfer equations by coupling, and the compressible flow phenomena inside the valves are studied focusing on the shock structures. . Fluid-structure interaction is considered using freely moving grid deformations. The flow patterns of subsonic acceleration, choked flow, supersonic expansion, and a strong curved shock were observed inside the valve during on/off operations. The subsonic flow acceleration affected the operation characteristics of the valve.

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Markovic, Zoran, Slobodan Stupar, Mirko Dinulovic, Ognjen Pekovic, Predrag Stefanovic y Dejan Cvetinovic. "Assessment results of fluid-structure interaction numerical simulation using fuzzy logic". Thermal Science 20, suppl. 1 (2016): 235–50. http://dx.doi.org/10.2298/tsci160111083m.

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A fuzzy approximation concept is applied in order to predict results of coupled computational structure mechanics and computational fluid dynamics while solving a problem of steady incompressible gas flow through thermally loaded rectangular thin-walled channel. Channel wall deforms into wave - type shapes depending on thermal load and fluid inlet velocity inducing the changes of fluid flow accordingly. A set of fluid - structure interaction (FSI) numerical tests have been defined by varying the values of fluid inlet velocity, temperature of inner and outer surface of the channel wall and numerical grid density. The unsteady Navier-Stokes equations are numerically solved using an element-based finite volume method and second order backward Euler discretization scheme. The structural model is solved by finite element method including geometric and material nonlinearities. The implicit two-way iterative code coupling, partitioned solution approach, were used while solving these numerical tests. Results of numerical analysis indicate that gravity and pressure distribution inside the channel contributes to triggering the shape of deformation. In the inverse problem, the results of FSI numerical simulations formed a database of input variables for development fuzzy logic based models considering downstream pressure drop and maximum stresses as the objective functions. Developed fuzzy models predicted targeting results within a reasonable accuracy limit at lower computation cost compared to series of FSI numerical calculations. Smaller relative difference were obtained when calculating the values of pressure drop then maximal stresses indicating that transfer function influence on output values have to be additionally investigated.

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EL BAROUDI, ADIL y FULGENCE RAZAFIMAHERY. "THEORETICAL AND NUMERICAL INVESTIGATIONS OF FREQUENCY ANALYSIS OF TWO CIRCULAR CYLINDERS OSCILLATING IN A INCOMPRESSIBLE VISCOUS FLUID". International Journal of Applied Mechanics 06, n.º 05 (octubre de 2014): 1450049. http://dx.doi.org/10.1142/s1758825114500495.

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A potential flow is presented in this paper for the analysis of the fluid-structure interaction systems including, but not limited to, the idealized human head. The model considers a cerebro-spinal fluid (CSF) medium interacting with two solid domain. The fluid field is governed by the linearized Navier–Stokes equation. A potential technique is used to obtain a general solution for a problem. The method consists in solving analytically partial differential equations obtained from the linearized Navier–Stokes equation. From the solution, modal shapes and stokes cells are shown. In the analysis, the elastic skull model and the rigid skull model are presented. A finite element analysis is also used to check the validity of the present method. The results from the proposed method are in good agreement with numerical solutions. The effects of the fluid thickness is also investigated.

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Nie, Shuai, Yihua Cao y Zhenlong Wu. "Numerical simulation of parafoil inflation via a Robin–Neumann transmission-based approach". Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 232, n.º 4 (24 de enero de 2017): 797–810. http://dx.doi.org/10.1177/0954410016688925.

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In this paper, a partitioned coupled iterative approach based on the Robin–Neumann transmission condition is proposed for the fluid–structure interaction simulation of the inflation process of a parafoil. The Reynold-averaged Navier–Stokes equations and the versatile finite element method are employed to solve the fluid flow field and the structural deformation, respectively. The generalized-α time integration scheme for the structure and the second order back Euler scheme for the fluid are incorporated in the Robin-Neumann method. A modified spring-transfinite interpolation hybrid method is exploited to detect the deformation of the grid and regenerate the grid for the fluid architecture. Both a two-dimensional case and a three-dimensional case are studied to examine the feasibility of the present approach. The simulation results reveal the evolution of the flow regime during the inflation process when the air pours into the parafoil. The whole inflation process can be concluded as two stages: the span-wise deployment and the longitudinal expansion. The numerical aerodynamic performance agrees well with that obtained by wind-tunnel experiment, suggesting the effectiveness of this method in handling such a highly nonlinear fluid–structure interaction in parachute inflation.

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CAO, YIHUA, QIANFU SONG, ZHUO WU y JOHN SHERIDAN. "FLOW FIELD AND TOPOLOGICAL ANALYSIS OF HEMISPHERICAL PARACHUTE IN LOW ANGLES OF ATTACK". Modern Physics Letters B 24, n.º 15 (20 de junio de 2010): 1707–25. http://dx.doi.org/10.1142/s0217984910023323.

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For analyzing the flow field and topological structure of hemispherical parachute in low angles of attack, a fluid-structure interaction (FSI) simulation technique is established to decide the shape of the hemispherical parachute during terminal descent. In the fluid simulation, the semi-implicit method for pressure-linked equations consistent (SIMPLEC) algorithm is introduced to solve shear stress transport (SST) k–ω turbulence Navier–Stokes (N–S) Equations. This method is proved to be efficient and stable by the experiment and corresponding numerical simulation. After obtaining the stable shape of the canopy, the parachute in different angles and velocities are considered.

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Zhu, Hongjun, Hongnan Zhao, Qian Pan y Xue Li. "Coupling Analysis of Fluid-Structure Interaction and Flow Erosion of Gas-Solid Flow in Elbow Pipe". Advances in Mechanical Engineering 6 (1 de enero de 2014): 815945. http://dx.doi.org/10.1155/2014/815945.

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A numerical simulation has been conducted to investigate flow erosion and pipe deformation of elbow in gas-solid two-phase flow. The motion of the continuous fluid phase is captured based on calculating three-dimensional Reynolds-averaged-Navier-Stokes (RANS) equations, while the kinematics and trajectory of the discrete particles are evaluated by discrete phase model (DPM), and a fluid-structure interaction (FSI) computational model is adopted to calculate the pipe deformation. The effects of inlet velocity, pipe diameter, and the ratio of curvature and diameter on flow feature, erosion rate, and deformation of elbow are analyzed based on a series of numerical simulations. The numerical results show that flow field, erosion rate, and deformation of elbow are all sensitive to the structural changes and inlet condition changes. Higher inlet rate, smaller curvature diameter ratio, or smaller pipe diameter leads to greater deformation, while slower inlet rate, larger curvature diameter ratio, and larger pipe diameter can weaken flow erosion.

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Lara, Javier, Inigo Javier Losada, Manuel Del Jesus, Gabriel Barajas y Raul Guanche. "IH-3VOF: A THREE-DIMENSIONAL NAVIER-STOKES MODEL FOR WAVE AND STRUCTURE INTERACTION". Coastal Engineering Proceedings 1, n.º 32 (27 de enero de 2011): 55. http://dx.doi.org/10.9753/icce.v32.waves.55.

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This paper describes the capability of a new model, called IH-3VOF to simulate wave-structure interaction problems using a three-dimensional approach. The model is able to deal with physical processes associated with wave interaction with porous structures. The model considers the VARANS equations, a volume-averaged version of the traditional RANS (Reynolds Averaged Navier-Stokes) equations. Turbulence is modeled using a k- approach, not only at the clear fluid region (outside the porous media) but also inside the porous media. The model has been validated using laboratory data of free surface time evolution in a fish tank containing a porous dam. Numerical simulations were calibrated by adjusting the porous flow empirical coefficients for two granular material characteristics. Sensitivity analysis of porous parameters has also been performed. The model is proven to reproduce with a high degree of agreement the free surface evolution during the seeping process. Simulations of a three- dimensional porous dam breaking problem has been studied, showing the excellent performance of the model in reproducing fluid patterns around a porous structure. The model is powerful tool to examine the near-field flow characteristics around porous structures in three dimensional flow conditions.

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Chern, Ming-Jyh, Dedy Zulhidayat Noor, Ching-Biao Liao y Tzyy-Leng Horng. "Direct-Forcing Immersed Boundary Method for Mixed Heat Transfer". Communications in Computational Physics 18, n.º 4 (octubre de 2015): 1072–94. http://dx.doi.org/10.4208/cicp.151214.250515s.

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AbstractA direct-forcing immersed boundary method (DFIB) with both virtual force and heat source is developed here to solve Navier-Stokes and the associated energy transport equations to study some thermal flow problems caused by a moving rigid solid object within. The key point of this novel numerical method is that the solid object, stationary or moving, is first treated as fluid governed by Navier-Stokes equations for velocity and pressure, and by energy transport equation for temperature in every time step. An additional virtual force term is then introduced on the right hand side of momentum equations in the solid object region to make it act exactly as if it were a solid rigid body immersed in the fluid. Likewise, an additional virtual heat source term is applied to the right hand side of energy equation at the solid object region to maintain the solid object at the prescribed temperature all the time. The current method was validated by some benchmark forced and natural convection problems such as a uniform flow past a heated circular cylinder, and a heated circular cylinder inside a square enclosure. We further demonstrated this method by studying a mixed convection problem involving a heated circular cylinder moving inside a square enclosure. Our current method avoids the otherwise requested dynamic grid generation in traditional method and shows great efficiency in the computation of thermal and flow fields caused by fluid-structure interaction.

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Cavallaro, Luca, Fabio Dentale, Giovanna Donnarumma, Enrico Foti, Rosaria E. Musumeci y Eugenio Pugliese Carratelli. "RUBBLE MOUND BREAKWATER OVERTOPPING: ESTIMATION OF THE RELIABILITY OF A 3D NUMERICAL SIMULATION". Coastal Engineering Proceedings 1, n.º 33 (25 de octubre de 2012): 8. http://dx.doi.org/10.9753/icce.v33.structures.8.

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Until recently, physical models were the only way to investigate into the details of breakwaters behavior under wave attack. From the numerical point of view, the complexity of the fluid dynamic processes involved has so far hindered the direct application of Navier-Stokes equations within the armour blocks, due to the complex geometry and the presence of strongly non stationary flows, free boundaries and turbulence. In the present work the most recent CFD technology is used to provide a new and more reliable approach to the design analysis of breakwaters, especially in connection with run-up and overtopping. The solid structure is simulated within the numerical domain by overlapping individual virtual elements to form the empty spaces delimited by the blocks. Thus, by defining a fine computational grid, an adequate number of nodes is located within the interstices and a complete solution of the full hydrodynamic equations is carried out. In the work presented here the numerical simulations are carried out by integrating the three-dimensional Reynolds Average Navier-Stokes Equations coupled with the RNG turbulence model and a Volume of Fluid Method used to handle the dynamics of the free surface. The aim of the present work is to investigate the reliability of this approach as a design tool. Two different breakwaters are considered, both located in Southern Sicily: one a typical quarry stone breakwater, another a more complex design incorporating a spill basin and an armoured layer made up by Coreloc® blocks.

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Tesis sobre el tema "Navier-Stokes equations. Numerical grid generation (Numerical analysis) Fluid-structure interaction"

Singh, Rajkeshar. "Application of generalized grids to turbomachinery CFD simulations". Thesis, Mississippi State : Mississippi State University, 2002. http://library.msstate.edu/etd/show.asp?etd=etd-07242002-230653.

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Nichols, Dudley Stephen. "Development of a free surface method utilizing an incompressible multi-phase algorithm to study the flow about surface ships and underwater vehicles". Diss., Mississippi State : Mississippi State University, 2002. http://library.msstate.edu/etd/show.asp?etd=etd-07112002-163134.

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Fouchet-Incaux, Justine. "Modélisation, analyse numérique et simulations autour de la respiration". Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112043.

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Cette thèse est consacrée à la modélisation de la ventilation mécanique chez l'humain et à l'analyse numérique des systèmes en découlant. Des simulations directes d'écoulement d'air dans l'ensemble des voies aériennes étant impossibles (maillages indisponibles et géométrie trop complexe), il est nécessaire de considérer un domaine d'intérêt réduit, qui implique de travailler dans une géométrie tronquée, comportant des frontières artificielles ou encore de considérer des modèles réduits simples mais représentatifs. Si on cherche à effectuer des simulations numériques 3D où l'écoulement du fluide est décrit par les équations de Navier-Stokes, différentes problématiques sont soulevées :- Si on considère que la ventilation est la conséquence de différences de pression, les conditions aux limites associées sont des conditions de type Neumann. Cela aboutit à des questions théoriques en terme d'existence et d'unicité de solution et à des questions numériques en terme de choix de schémas et de méthodes adaptées.- Lorsque l'on travaille dans un domaine tronqué, il peut être nécessaire de prendre en compte les phénomènes non décrits grâce à des modèles réduits appropriés. Ici nous considérons des modèles 0D. Ces couplages 3D/0D sont à l'origine d'instabilités numériques qu'on étudie mathématiquement et numériquement dans ce manuscrit. Par ailleurs, lorsqu'on s'intéresse à des régimes de respiration forcée, les modèles usuels linéaires sont invalidés par les expériences. Afin d'observer les différences entre les résultats expérimentaux et numériques, il est nécessaire de prendre en compte plusieurs types de non linéarités, comme la déformation du domaine ou les phénomènes de type Bernoulli. Une approche par modèles réduits est adoptée dans ce travail.Pour finir, on a cherché à valider les modèles obtenus en comparant des résultats numériques et des résultats expérimentaux dans le cadre d'un travail interdisciplinaire.Parvenir à modéliser et simuler ces écoulements permet de mieux comprendre les phénomènes et paramètres qui entrent en jeu lors de pathologies (asthme, emphysème...). Un des objectifs à moyen terme est d'étudier l'influence du mélange hélium-oxygène sur le dépôt d'aérosol, toujours dans le cadre du travail interdisciplinaire. A plus long terme, l'application de ces modèles à des situations pathologiques pourrait permettre de construire des outils d'aide à la décision dans le domaine médical (compréhension de la pathologie, optimisation de thérapie...)
In this thesis, we study the modelling of the human mecanical ventilation and the numerical analysis of linked systems. Direct simulations of air flow in the whole airways are impossible (complex geometry, unavailable meshes). Then a reduced area of interest can be considered, working with reduced geometries and artificial boundaries. One can also use reduced models, simple but realistic. If one try to make 3D numerical simulations where the fluid flow is described by the Navier-Stokes equations, various issues are raised:- If we consider that ventilation is the result of pressure drops, the associated boundary conditions are Neumann conditions. It leads to theoretical questions in terms of existence and uniqueness of solution and numerical issues in terms of scheme choice and appropriate numerical methods.- When working in a truncated domain, it may be necessary to take into account non-described phenomena with appropriate models. Here we consider 0D models. These 3D/0D couplings imply numerical instabilities that we mathematically and numerically study in this thesis.Furthermore, when we focus on forced breathing, linear usual models are invalidated by experiments. In order to observe the differences between the experimental and numerical results, it is necessary to take into account several types of non-linearities, such as deformation of the domain or the Bernoulli phenomenon. A reduced model approach is adopted in this work. Finally, we sought to validate the obtained models by comparing numerical and experimental results in the context of interdisciplinary work.Achieving model and simulate these flows allow to better understand phenomena and parameters that come into play in diseases (asthma, emphysema ...). A medium-term objective is to study the influence of helium-oxygen mixture in the aerosol deposition. In the longer term, the application of these models to pathological situations could afford to build decision support tools in the medical field (understanding of pathology, therapy optimization ...)

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Ahn, Hyung Taek. "A new incompressible Navier-Stokes method with general hybrid meshes and its application to flow/structure interactions". Thesis, 2005. http://hdl.handle.net/2152/1493.

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Ahn, Hyung Taek Dawson Clinton N. Kallinderis Y. "A new incompressible Navier-Stokes method with general hybrid meshes and its application to flow/structure interactions". 2005. http://repositories.lib.utexas.edu/bitstream/handle/2152/1493/ahnd20038.pdf.

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Lapierre, David. "Simulation de la nage anguilliforme". Thèse, 2014. http://hdl.handle.net/1866/11107.

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Ce document traite premièrement des diverses tentatives de modélisation et de simulation de la nage anguilliforme puis élabore une nouvelle technique, basée sur la méthode de la frontière immergée généralisée et la théorie des poutres de Reissner-Simo. Cette dernière, comme les équations des fluides polaires, est dérivée de la mécanique des milieux continus puis les équations obtenues sont discrétisées afin de les amener à une résolution numérique. Pour la première fois, la théorie des schémas de Runge-Kutta additifs est combinée à celle des schémas de Runge-Kutta-Munthe-Kaas pour engendrer une méthode d’ordre de convergence formel arbitraire. De plus, les opérations d’interpolation et d’étalement sont traitées d’un nouveau point de vue qui suggère l’usage des splines interpolatoires nodales en lieu et place des fonctions d’étalement traditionnelles. Enfin, de nombreuses vérifications numériques sont faites avant de considérer les simulations de la nage.
This paper first discusses various attempts at modeling and simulating anguilliform swimming, then we develop a new technique, based on a method of generalized immersed boundary and the beam theory of Reissner-Simo. Subsequent to the derivation of the equations of polar fluids, the beam theory is derived from continuum mechanics and the resulting equations are then discretized, allowing a numerical solution. For the first time, the theory of additive Runge-Kutta schemes are combined with the Runge-Kutta-Munthe-Kaas method to generate schemes of arbitrarily high formal order of convergence. Moreover, the interpolation and spreading operations are handled from a new point of view that suggests the use of interpolatory nodal splines instead of spreading traditional functions. Finally, many numerical verifications are done before considering simulations of swimming.

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Libros sobre el tema "Navier-Stokes equations. Numerical grid generation (Numerical analysis) Fluid-structure interaction"

Mavriplis, Dimitri. Parallel performance investigations of an unstructured mesh Navier-Stokes solver. Hampton, Va: Institute for Computer Applications in Science and Engineering, NASA Langley Research Center, 2000.

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Frink, Neal T. Tetrahedral finite-volume solutions to the Navier-Stokes equations on complex configurations. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1998.

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Mavriplis, Dimitri. Large-scale parallel viscous flow computations using an unstructured multigrid algorithm. Hampton, VA: Institute for Computer Applications in Science and Engineering, NASA Langley Research Center, 1999.

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Topology and grid adaption for high-speed flow computations. Norfolk, Va: Dept. of Mechanical Engineering and Mechanics, College of Engineering and Technology, Old Dominion University, 1988.

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Z, Pirzadeh Shahyar y Langley Research Center, eds. Tetrahedral finite-volume solutions to the Navier-Stokes equations on complex configurations. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1998.

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Institute for Computer Applications in Science and Engineering., ed. Large-scale parallel viscous flow computations using an unstructured multigrid algorithm. Hampton, VA: Institute for Computer Applications in Science and Engineering, NASA Langley Research Center, 1999.

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Actas de conferencias sobre el tema "Navier-Stokes equations. Numerical grid generation (Numerical analysis) Fluid-structure interaction"

Chen, Larry y Urmila Ghia. "Composite Solution Procedure for 3-D Flow Simulations on a Multi-Box Grid". En ASME 2006 2nd Joint U.S.-European Fluids Engineering Summer Meeting Collocated With the 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/fedsm2006-98441.

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Fluid flows in biological systems are typically complex, due to factors such as non-Newtonian behavior of biochemical fluids and complex geometry, as well as the interaction of muscles and fluid. With the advent of modern computational technology, these problems are gradually resolved. The present research illustrates two such examples. Grid generation is essential for conducting numerical simulation of fluid flow. In the present research, a new grid generation technique is developed and implemented into a flow solver. This technique enables one to create a grid for complex geometry using only a single computational zone. The flow field can therefore be analyzed without iteration between zones. The numerical scheme developed for solving the grid generation equations is an extension of the traditional three-dimensional Douglass-Gunn Alternating-Direction Implicit (ADI) scheme. A unique feature of the demonstrated grid generation scheme is the concept of multi-box computational domains. In this scheme, the physical domain is mapped onto a multi-box geometry in the computational space, rather than a single box as the traditional methods do. Therefore, the numerical scheme is adjusted accordingly. Flow simulations were performed using the software INS3D, which employs the method of artificial compressibility. This method transforms the Navier-Stokes equations into a system of hyperbolic-parabolic equations, and then marches along the pseudo-time axis until the velocity field becomes divergence-free. Two biological flow problems were analyzed using the aforementioned method. The flow field in an arterial graft as well as in the Left atrium (LA) of the human heart was studied. The effect of Reynolds number and flow-division ratio is examined in the graft problem. The Reynolds number effect is demonstrated via the presence of a helical flow structure and the overall pressure drop. The flow-division ratio alters the flow field in a way that moves the stagnation points. The simulated flow field closely resembles that observed clinically. The steady-state simulation of the flow field in the left atrium of the human heart provided information about the long-term performance of the heart chamber. The simulation demonstrates the existence of low wall shear region, which is therefore susceptible to blood clot formation. This observation also agrees with the clinical findings. In summary, the present research demonstrates application of CFD techniques in the analysis of flow in a biological system. A new grid generation technique is realized, and proved to be useful in simulating these flows. The flow simulation results provide insights into the system, and may be useful for clinical reference.

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Li, Han, Huhu Wang, Yassin A. Hassan y N. K. Anand. "Computational Fluid Dynamics Analysis of Two Parallel Rectangular Jets Using OpenFOAM". En 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-61046.

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Two or multiple parallel jets are an important shear flow that widely existing in many industrial applications. The interaction between turbulence jets enables fast and thorough mixing of two fluids. The mixing feature of parallel jets has many engineering applications, such as, in Generation IV conceptual nuclear reactors, the coolants merge in upper or lower plenum after passing through the reactor core. While study of parallel jets mixing phenomenon, numerical experiments such as Computational Fluid Dynamics (CFD) simulations are extensively incorporated. Validation of varied turbulent models is of importance to make sure that the numerical results could be trusted and served as a guideline further design purpose. Many commercial CFD packages in the market such as FLUENT and Star CCM+ can provide the ability to simulate turbulent flow with predefined turbulence model, however, such commercial solvers may lack the flexibility that allow users build their own models for R&D purpose. The existing solvers in OpenFOAM are developed to fulfill both academic and industrial needs by achieving large-scale computational capability with a variety of physical models. Moreover, as an open source CFD toolbox, OpenFOAM grants users full control of the source code with complete freedom of customization. The purpose of this study is to perform CFD simulation using OpenFOAM for two submerged parallel jets issuing from two rectangular channels. Fully hexahedron multi-density mesh is generated using blockMesh utility to ensure velocity gradients are properly evaluated. A generalized-multi-grid solver is used to enhance convergence. Based on Reynolds-Averaged Navier-Stokes Equations (RANS), the realizable k-ε and k-ε shear stress transport (SST) are selected to model turbulent flow. Steady state Finite Volume solver simpleFoam is used to perform the simulation. In addition, data from experiments run in Thermal-Hydraulic Lab at Texas A&M University using particle image velocity (PIV) and Laser Doppler Anemometry (LDA) methods are considered in order to compare and validate simulation results. A number of turbulence characteristic such as mean velocities, turbulent intensities, z-component vorticity were compared with experiments. It was found that for stream-wise mean velocity profile as well as shear stresses, the realizable k-ε model exhibits a good agreement with experimental data. However, velocity fluctuation and turbulence intensities, simulation results showed a certain discrepancy.

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Rajaomazava, Tolotra Emerry, Mustapha Benaouicha y Jacques-André Astolfi. "Numerical Analysis of Hydrofoil Dynamics by Using a Fluid-Structure Interaction Approach". En ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78389.

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In this paper, the flow over pitching and heaving hydrofoil is investigated. The viscous incompressible Navier-Stokes problem in Arbitrary Lagrangian-Eulerian (ALE) formulation is solved using the finite elements code Cast3M. The projection method is used to uncouple the velocity and pressure fields. The implicit Euler scheme is applied for time discretization of fluid equations. The dynamics of the hydrofoil is governed by a non-linear ordinary differential equation. The non-linear coupled problem is solved using the explicit staggered algorithm. The effects of fluid-structure interaction on hydrofoil dynamics and pressure center position are analyzed.

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Ebna Hai, Bhuiyan Shameem Mahmood. "Numerical Approximation of Fluid Structure Interaction (FSI) Problem". En ASME 2013 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/fedsm2013-16013.

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Nowadays, advanced composite materials such as carbon fiber reinforced plastics (CFRP) are being applied to many aircraft structures in order to improve performance and reduce weight. Most composites have strong, stiff fibres in a matrix which is weaker and less stiff. However, aircraft wings can break due to Fluid-Structure Interaction (FSI) oscillations or material fatigue. The airflow around an airplane wing causes the wing to deform, while a wing deformation causes a change in the air pattern around it. Due to thrust force, turbulent flow and high speed, fluid-structure interaction (FSI) is very important and arouses complex mechanical effects. Due to the non-linear properties of fluids and solids as well as the shape of the structures, only numerical approaches can be used to solve such problems. The principal aim of this research is to explore and understand the behaviour of the fluid-structure interaction during the impact of a deformable material (e.g. an aircraft wing) on air. This project focuses on the analysis of Navier-Stokes and elastodynamic equations in the arbitrary Lagrangian-Eulerian (ALE) frameworks in order to numerically simulate the FSI effect on a double wedge airfoil. Since analytical solutions are only available in special cases, the equation needs to be solved by numerical methods. Of all methods, the finite element method was chosen due to its special characteristics and for its implementation, the software package DOpElib.

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Sargentini, Lucia, Benjamin Cariteau y Morena Angelucci. "Experimental and Numerical Analysis for Fluid-Structure Interaction for an Enclosed Hexagonal Assembly". En ASME 2014 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/pvp2014-28053.

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This paper is related to fluid-structure interaction analysis of sodium cooled fast reactors core (Na-FBR). Sudden liquid evacuation between assemblies could lead to overall core movements (flowering and compaction) causing variations of core reactivity. The comprehension of the structure behavior during the evacuation could improve the knowledge about some SCRAMs for negative reactivity occurred in PHÉNIX reactor and could contribute on the study of the dynamic behavior of a FBR core. An experimental facility (PISE-2c) is designed composed by a Poly-methyl methacrylate hexagonal rods (2D-plan similitude with PHÉNIX assembly) with a very thin gap between assemblies. Another experimental device (PISE-1a) is designed and composed by a single hexagonal rod for testing the dynamic characteristics. Different experiments are envisaged: free vibrations and oscillations during water injection. A phenomenological analysis is reported showing the flow behavior in the gap and the structure response. Also computational simulations are presented in this paper. An efficient numerical method is used to solve Navier-Stokes equations coupled with structure dynamic equation. The numerical method is verified by the comparison of analytic models and experiments.

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Sigrist, Jean Franc¸ois, Christian Laine, Dominique Lemoine y Bernard Peseux. "Choice and Limits of a Fluid Model for the Numerical Study in Dynamic Fluid Structure Interaction Problems". En ASME 2003 Pressure Vessels and Piping Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/pvp2003-1820.

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This paper is related to the study of a nuclear propulsion reactor prototype for the French Navy. This prototype is built on ground and is to be dimensioned toward seismic loading. The dynamic analysis takes the coupled fluid structure analysis into account. The basic fluid models used by design engineers are inviscid incompressible or compressible. The fluid can be described in a bidimensional by slice or a three-dimensional approach. A numerical study is carried out on a generic problem for the linear FSI dynamic problem. The results of this study are presented and discussed. As a conclusion, the three-dimensional inviscid incompressible fluid appears to be the best compromise between the description of physical phenomena and the cost of modeling. The geometry of the reactor is such that large displacements of the structure in the fluid can occur. Therefore, the linearity hypothesis might not be longer valid. The case of large amplitude imposed oscillating motion of a cylinder in a confined fluid is numerically studied. A CFD code is used to investigate the fluid behavior solving the NAVIER-STOKES equations. The forces induced on the cylinder by the fluid are computed and compared to the linear solution. The limit of the linear model can then be exhibited.

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Desbonnets, Quentin y Daniel Broc. "Fluid Structure Interaction Modelling for the Vibration of Tube Bundles: Part I—Analysis of the Fluid Flow in a Tube Bundle". En ASME 2011 Pressure Vessels and Piping Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/pvp2011-57578.

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It is well known that a fluid may strongly influence the dynamic behaviour of a structure. Many different physical phenomena may take place, depending on the conditions: fluid flow, fluid at rest, little or high displacements of the structure. Inertial effects can take place, with lower vibration frequencies, dissipative effects also, with damping, instabilities due to the fluid flow (Fluid Induced Vibration). In this last case the structure is excited by the fluid. Tube bundles structures are very common in the nuclear industry. The reactor cores and the steam generators are both structures immersed in a fluid which may be submitted to a seismic excitation or an impact. In this case the structure moves under an external excitation, and the movement is influence by the fluid. The main point in such system is that the geometry is complex, and could lead to very huge sizes for a numerical analysis. Homogenization models have been developed based on the Euler equations for the fluid. Only inertial effects are taken into account. A next step in the modelling is to build models based on the homogenization of the Navier-Stokes equations. The papers presents results on an important step in the development of such model: the analysis of the fluid flow in a oscillating tube bundle. The analysis are made from the results of simulations based on the Navier-Stokes equations for the fluid. Comparisons are made with the case of the oscillations of a single tube, for which a lot of results are available in the literature. Different fluid flow pattern may be found, depending in the Reynolds number (related to the velocity of the bundle) and the Keulegan-Carpenter number (related to the displacement of the bundle). A special attention is paid to the quantification of the inertial and dissipative effects, and to the forces exchanges between the bundle and the fluid. The results of such analysis will be used in the building of models based on the homogenization of the Navier-Stokes equations for the fluid.

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Morinishi, Koji y Tomohiro Fukui. "Fluid-Structure Interactive Simulation Using a Virtual Flux Method". En ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-20011.

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This paper describes the resent development of a virtual flux method for simulating fluid-structure interaction problems. The virtual flux method is one of the sharp interface Cartesian grid methods. The numerical flux across the interface is replaced with the virtual flux so that proper interface conditions must be satisfied there. In this study, the virtual flux method is applied to numerical flow simulations about reciprocating engines. The compressible Navier-Stokes equations are coupled with the equation of motion of the piston, connecting rod, and crank system. Intake and exhaust valves are lifted up and down according with the crank angle in the intake and exhaust strokes. Instead of modeling the complex fuel combustion process, a proper amount of energy is added to the Navier-Stokes equation at the beginning of each expansion stroke, to retain the four stroke engine cycle at a constant revolution rate. Initially the engine is started by starter motor force, which is added for a few seconds. The engine comes to work at the revolution rate intended after some initial transition cycles. With designing the intake and exhaust valve lift properly, intake mass and revolution rate are improved by several percent. It is confirmed that the virtual flux method is easily applicable to the simulation of fluid-structure interaction problems.

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Broc, Daniel y Quentin Desbonnets. "Fluid Structure Interaction Modelling for the Vibration of Tube Bundles: Part II—Homogenization Method Based on the Navier Stokes Equations". En ASME 2011 Pressure Vessels and Piping Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/pvp2011-57586.

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It is well known that a fluid may strongly influence the dynamic behaviour of a structure. Many different physical phenomena may take place, depending on the conditions: fluid at rest, fluid flow, little or high displacements of the structure. Inertial effects can take place, with lower vibration frequencies, dissipative effects also, with damping, instabilities due to the fluid flow (Fluid Induced Vibration). In this last case the structure is excited by the fluid. The paper deals with the vibration of tube bundles in a fluid, under a seismic excitation or an impact. In this case the structure moves under an external excitation, and the movement is influenced by the fluid. The main point in such system is that the geometry is complex, and could lead to very huge sizes for a numerical analysis. Many works has been made in the last years to develop homogenization methods for the dynamic behaviour of tube bundles. The size of the problem is reduced, and it is possible to make numerical simulations on wide tubes bundles with reasonable computer times. These homogenization methods are valid for “little displacements” of the structure (the tubes), in a fluid at rest. The fluid movement is governed by the linear Euler equations (without the convective term). In this case, only “inertial effects” will take place, with globally lower frequencies. It is well known that dissipative effects due to the fluid may take place, even if the displacements of the tube are no so high, or if the fluid is not still. Such effects may be described in the homogenized models by using a Rayleigh damping, but the basic assumption of the model remains the “perfect fluid” hypothesis. It seem necessary, in order to get a best description of the physical phenomena, to build a more general model, based on the general Navier Stokes equation for the fluid. The homogenization of such system will be much more complex than for the Euler equations. The paper presents the first step in the building of a method based on the homogenization of the Navier Stokes equations.

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Dorney, Daniel J. y Roger L. Davis. "Centrifugal Compressor Impeller Aerodynamics: A Numerical Investigation". En ASME 1990 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1990. http://dx.doi.org/10.1115/90-gt-213.

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A three-dimensional, Navier-Stokes analysis is presented for the prediction of viscous flows through centrifugal impellers. Based on the Navier-Stokes rotor/stator interaction procedure developed by Rai, the present analysis uses a zonal grid methodology to discretize the impeller flow field and to facilitate the relative motion of the impeller. A blade surface oriented O-grid generated from an elliptic partial differential equation solution procedure is patched into an algebraically generated H-grid which is used to discretize the inlet, exit and blade-to-blade regions. The equations of motion are integrated using a spatially third-order accurate, implicit, iterative, upwind, finite difference, time-marching technique. Predicted results are presented for flow through a low speed centrifugal compressor impeller operating at design flow conditions. Comparison of these predicted results with experimental data demonstrates the capability of this procedure to predict impeller blade loading and provide insight into the secondary flow structure within the impeller blade passage.

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