Tesis sobre el tema "Impact fluide-Structure"
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Aquelet, Nicolas. "Modélisation de l'impact hydrodynamique par un couplage fluide-structure". Lille 1, 2004. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2004/50376-2004-Aquelet.pdf.
Texto completoConstantinescu, Adrian. "Modélisation 2D de l’impact d’une structure sur l’eau : initiation de l’endommagement". Brest, 2006. http://www.theses.fr/2006BRES2037.
Texto completoThe research work in this thesis covers the modeling of the impact of a 2D body with water and the subsequent appearance of macroscopic fractures. The main application is the modeling of the slamming forces acting on the ship structure in severe sea conditions. The time-dependent stresses and strains on a ship hull can provoke a premature mechanical failure due to fatigue. The main work consists in the development and validation of a numerical tool (lmpact++ ABAQUS) simulating the fluid-structure interaction during the violent impact of a body of a simple geometry (wedge, cone, cylinder, sphere, axisymmetric parabolic body, ellipsoid, etc) on a free water surface. This approach considers the effect of the deformation of the structure on the flow and vive versa. The numerical tool is based on the commercial finite element code ASAQUS and permits to calculate thee stresses and deformations, energies and the global forces for a 2D solid structure inipacting a fluid. In view of the long-term goal of aiding structural design of ships, the second objective was to bring a quantitative and qualitative representation of the beginning of the damage of a metallic structure impacting water, namely to predict the time and location of fracture initiation due to repeated slamming impacts. These phenomena are modeled here by a bifurcation of the solution for the velocity in the mechanical equilibrium equation for the deformable body
Berkane, Belaid. "Etudes expérimentales de l'influence de l'aératiοn sur les impacts hydrοdynamiques : deux cοnfiguratiοns idéalisées avec présence de pοches d'air et de bulles". Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMLH04.
Texto completoHydrodynamic impacts between solid structures and liquids play a crucial role in various strategic fields such as coastal engineering, aeronautics, and renewable energy. This thesis focuses on the less explored effect of aeration, where the presence of air in the form of bubbles or air pockets significantly alters impact forces and hydrodynamic responses. The central objective of this thesis is to deepen our understanding of aeration's effects on complex hydrodynamic impact dynamics. This research concentrates on two distinct experimental setups: the impact of a flat plate on a calm water surface and the impact of an aerated water jet on a flat plate. The challenge is to examine how aeration influences impact pressures and post-impact oscillation frequencies. To achieve these objectives, experimental setups were designed for each case study. These model experiments allow us to precisely control crucial parameters such as impact velocity, plate dimensions, ambient pressure, etc. Special attention was also given to measuring aeration rates and impact pressures, enabling rigorous analysis of the results. For the plate impact, observations showed that maximum impact pressures and pressure impulses deviate from the von Karman theory, mainly due to the damping effect of air. Reducing ambient pressure increases impact pressures, suggesting a reduction of the air cushion effect. Regarding the impact of an aerated water jet, a diversity of flow regimes, such as bubble, slug, churn, and annular flows, were identified. The interaction between the number of injectors, air pressure, and bubble characteristics demonstrates a significant interdependence. The effects of aeration on impact pressures and oscillation frequencies show that larger structures induce slower oscillations and increased dimensionless pressures
Halbout, Séverin. "Contribution à l'étude des interactions fluide-structure lors de l'impact hydrodynamique avec vitesse d'avance d'un système de flottabilité d'hélicoptère". Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10036.
Texto completoWhen operating on offshore conditions, helicopters may encounteremergency situations during which an immediate sealanding isrequired. In this case, the aircraft may experience a water impact event.Floatability systems are inflated to cushion the impact and toensure that the floatation is maintained while the crew evacuates.The dimensioning procedure of helicopter's floatability systemsremains very challenging. In this process, accurate prediction of thebehavior and the global loads on the helicopters floaters during ditchingis crucial. To obtain a better understanding of the floatability system,and to be able to develop more accurate models, the hydrodynamicalcharacteristics of the floaters, as flexible bodies, need to be furtherinvestigated. Experiments assessing the hydrodynamics characteristicsof these particular types of deformable bodies are rare. To this aim, anexperimental campaign has been carried out to identify the nature ofloads (global and local) and potential deformations. Numericalinvestigations are proposed to complete our understanding ofphenomena observed during experimental tests.An academic experimental campaign have been led in the flume of Ecole Centrale de Marseille. A baloon was drop from 0.5 to 2.4m with various inner pressure. Deformations and kinematics are measured and analysed before comparisons with a semi-analytical modelisation. Some results with the in-house software DITCHER are also proposed in this thesys
Ghaleb, Marie-Josèphe. "Vibrations d'une plaque élastique infinie couplée avec un fluide sous l'effet d'un impact ponctuel". Grenoble 1, 1987. http://www.theses.fr/1987GRE10150.
Texto completoBeaudet, Julien. "Caractérisations à très hautes températures de protections thermiques sous impact normal d'un jet chaud supersonique : influence du couplage aérothermique et des propriétés matériaux sur la tenue à l'ablation". Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2011. http://www.theses.fr/2011ESMA0016.
Texto completoThis study is focused on the characterizations of the ablative properties of different thermal protections for very high temperatures applications. Using a specific characterization method, the physical mechanisms involved during the ablation process have been identified. Two different test benches with a normal gas flow have been used in this investigation. The first one is laboratory test bench based on an oxyacetylene torch (conditions termed "thermal ablation" with a 3000°C gas temperature). The second one is a large scale facility producing a hot supersonic gas flow (Mach number = 3) and a temperature about 2000°C, leading to an "aerothermal ablation". Various composite materials have been tested by mixing different matrices, different architectures and different kind of fibers. Under thermal ablation condition (oxyacetylene torch), mass loss and surface recession are due to the thermo-oxidation reactions occurring both in the matrix and in the fibers. Once the pyrolysis reaction completed, a volatilization of the composite during the exposure is observed. In contrast, under aerothermal ablation conditions, surface recession is observed prior to the completion of the oxidation/pyrolysis reactions. Under such conditions, the degradation of local mechanical properties associated with the strong mechanical impact of the supersonic jet on the material leads to ablation. In parallel, a numerical model of ablation has been developed. One of the main requirements was to develop an engineering tool to design various types of thermal protection systems (e. G. Organic composite, ceramic composites…) and hence various ablation processes. This model is based on the oxidation/pyrolysis reactions kinetics. It has been identified for one composite material whose thermal parameters (i. E. Thermal conductivity, specific heat, density) have been fully characterized as a function of temperature and degradation state. First numerical simulations were compared to the experimental results on the oxyacetylene torch test to validate the model for a future extension of ablation modelling under aerothermal conditions
Malleron, Nicolas. "Contribution à l'étude des interactions fluide-structure pour l'analyse de l'impact hydrodynamique d'un système de flottabilité d'hélicoptère". Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2009. http://tel.archives-ouvertes.fr/tel-00457018.
Texto completoCaleyron, Fabien. "Simulation numérique par la méthode SPH de fuites de fluide consécutives à la déchirure d'un réservoir sous impact". Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00711040.
Texto completoMessahel, Ramzi. "ALE and SPH formulations for Fluid Structure Interaction : shock waves impact". Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10022/document.
Texto completoThis thesis focuses on the numerical study of the propagation of shock waves in compressible multiphase flows and fluid structure interaction. Two approaches are being studied for the numerical solution of the fluid part: the ALE approach (Arbitrary Lagrangian Eulerian) and the Lagrangian SPH (Smoothed Particle Hydrodynamics) approach; while the structure part is solved by a conventional FE (Finite Element). The numerical investigation of the ALE and SPH methods are the two main areas of research.Water Hammers phenomena occuring in nuclear industries are investigated in this thesis. During a Water Hammer, the shock waves reflections in nuclear piping may drop locally the water pressure below its saturation pressure and generate cavitation. The three equations HEM (Homogeneous Equilibrium Model) phase change model proposed by Saurel et al. (1999) is studied and applied to solve water hammers. The obtained results are compared with experimental data. Despite the use of renormalization techniques in SPH, instabilities (numerical oscillations) are developed at the interface between particles from different materials. These instabilities restrict the use of traditional SPH schemes to problems with low density ratio. In order to solve the shock problems in the compressible regime, the scheme originally proposed by Hu and Adams (2006) is adapted to fully compressible regime (FC-SPH) by considering the coupling between the density and the smoothing length. The different SPH schemes are compared for 1-D and 2-D multiphase shock problems. Validation is performed in comparison with exact solutions for 1-D problems and ALE solution for 2-D problems
Thebault, Martin. "Coherent structures and impact of the external thermal stratification in a transitional natural convection vertical channel". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1327/document.
Texto completoIn natural convective flows, complex coherent structures develop whose the role in heat and mass transfer are not well understood. A numerical study, based on Large-Eddy-Simulations of a vertical channel with one side uniformly was therefore carried out. Different stages of transitional flow development were identified numerically with two characteristic frequency bands being observed in the flow, near the heated wall. Methods derived from the Proper Orthogonal Decomposition (POD) was also used and allows the most energetic modes to be separated accordingly to two characteristic frequency bands found numerically. As result, the contribution of the two families of modes to the near wall turbulent heat transfer and velocity-temperature correlation has been evaluated. POD was also performed on experimental measurements showing similarities with the numerically observed structures.In this work, variations of the external thermal stratification have been identified as one possible source of these differences and its influence was therefore investigated experimentally and numerically. It is shown that the increase in the positive gradient of the external stratification not only decreases the mass flow rate but also displaces the transition height to a lower location in the channel. Numerical simulations also allow the study of cases of weak and negative thermal stratifications which are difficult to achieve in laboratories. A theoretical model of the influence of the external thermal stratification on the mass flow rate was also developed. There is an excellent agreement between the theoretical predictions and the experimentally and numerically obtained mass flow rates. This clearly highlights that external temperature distributions are key driving factors and their influence is accurately quantified in this work
Fortes-Patella, Regiane. "Analyse de l'érosion de cavitation par simulations numériques d'impacts". Grenoble INPG, 1994. http://www.theses.fr/1994INPG0018.
Texto completoBrandely, Anaïs. "Étude du ballottement de fluide dans les réservoirs à carburant : approches numérique et expérimentale". Thesis, Compiègne, 2016. http://www.theses.fr/2016COMP2274/document.
Texto completoThe present thesis focuses on an investigation of the sloshing phenomenon in a partially filled fuel tank submitted to a harmonic excitation motion. In the first part, the confrontation of numerical results between a linear approach - taking into account viscosity - and a nonlinear approach based on a commercial code leads to define a parameter of linearity. This parameter allows determining cases of sloshing who require non-linear resolution and those who need a linear theory to predict the phenomenon. An experimental study of fluid sloshing in a rectangular tank submitted to an automotive braking is conducted. Tests leaded allow measuring global forces engendered by the motion of the fluid, pressure of fluid impact and velocity field by PIV. This chapter provides an important data base and helps to investigate on the physical phenomenon. This study is completed by CFD results. To conclude, a numerical model for fluid-structure interactions is presented. Limits of this segregated partitioned coupling in case of sloshing in tank flexibly attached are highlighted, depending mostly on the mass ratio between fluid and tank structure. An added-mass term is integrated to the corrected staggered scheme ensuring systematically the convergence of the coupled solution and reducing significantly the iterations required
Nachtane, Mourad. "Énergies marines renouvelables et étude des performances des matériaux composites : cas d'une hydrolienne". Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2019. http://www.theses.fr/2019ENTA0010.
Texto completoRecently, Renewable Marine Energies (RME) has emerged as a tremendous opportunity for a real ecological and industrial choice to meet the growing demands for energy and also to fight global warming. The study conducted in this thesis is with in this framework of research and is focused on the investigation of one of the most promising categories of RMEs which is tidal current turbine. A new hydrofoil for the turbine was designed using BEM (Blade Element Momentum) methods and CFD (Computational Fluid Dynamics) calculations with improved hydrodynamic efficiency. Furthermore, a series of numerical studies were conducted to investigate and examine the damage behavior of composite materials under critical loadings by developing DLOAD and VUMAT routines. This numerical study assisted in understanding the problems of structural lightening, resistance to fatigue and impact loading, and other degradation phenomena of themechanical properties of a composite turbine in severe marine environments and solving the needs of the manufactures. Moreover, study about the dynamic behavior of a composite/composite bonded assembly was also conducted because joint assembly plays a vital role in reducing the mass of the structure which is of extreme relevance in the field of marine and offshore structures. Another important obstacle regarding the application of composite and bonded structures in marine was the control of hygro-mechanical coupling. Therefore in this context, additional campaign of tests was carried out on bonded composite specimens by studying the hygrothermal effect on their dynamic behavior at different deformation rates using Hopkinson bar method. This hybrid study of hygro-thermal effect of the dynamic properties of the bonded composites will aid in optimization of the structures and to move into the commercial phase with a substantial gain in LCOE (Levelized Cost of Energy) in future
Fillon, Blandine. "Développement d'un outil statistique pour évaluer les charges maximales subies par l'isolation d'une cuve de méthanier au cours de sa période d'exploitation". Thesis, Poitiers, 2014. http://www.theses.fr/2014POIT2337/document.
Texto completoThis thesis focuses on statistical tools for the assessment of maxima sloshing loads in LNG tanks. According to ship features, tank cargo and sailing conditions, a sloshing phenomenon is observed inside LNG tanks. The determination of sloshing loads supported by the tank structure is derived from impact pressure measurements performed on a test rig. Pressure maxima per impact, extracted from test measurements, are investigated. Test duration is equivalent to 5 hours in full scale. This duration is not sufficient to determine pressure maxima associated with high return periods (40 years). It is necessary to use a probabilistic model in order to extrapolate pressure maxima. Usually, a Weibull model is used. As we focus on extreme values from samples, fittings are also performed with the generalized extreme value distribution and the generalized Pareto distribution using block maximum method and peaks over threshold method.The originality of this work is based on the use of an alternate measurement system which is more relevant than usual measurement system to get pressure maxima and a 480 hours measured data available for same test conditions. This provides a reference distribution for pressure maxima which is used to assess the relevance of the selected probabilistic models. Particular attention is paid to the assessment of fittings quality using statistical tests and to the quantification of uncertainties on estimated values.The provided methodology has been implemented in a software called Stat_R which makes the manipulation and the treatment of results easier
Ahmad, Alexandre. "Animation de structures déformables et modélisation des interactions avec un fluide basées sur des modèles physiques". Limoges, 2007. https://aurore.unilim.fr/theses/nxfile/default/4f73d6f8-b8f0-4794-924b-8f827db44689/blobholder:0/2007LIMO4046.pdf.
Texto completoThe presented works' main focus is the interaction of liquids and thin shells, such as sheets of paper, fish fins and even clothes. Even though such interactions is an every day scenario, few research work in the computer graphics community have investigated this phenomenon. Thereby, I propose an algorithm which resolves contacts between Lagrangian fluids and deformable thin shells. Visual artefacts may appear during the surface extraction procedure due to the proximity of the fluids and the shells. Thus, to avoid such artefacts, I propose a visibility algorithm which projects the undesired overlapping volume of liquid onto the thin shells' surface. In addition, an intuitive parametrisation model for the definition of heterogeneous friction coefficients on a surface is presented. I also propose two optimisation methods. The first one reduces the well-known dependency of numerical stability and the timestep when using explicit schemes by filtering particles' velocities. This reduction is quantified with the use of frequency analysis. The second optimisation method is a unified dynamic spatial acceleration model, composed of a hierarchical hash table data structure, that speeds up the particle neighbourhood query and the collision broad phase. The proposed unified model is besides used to efficiently prune unnecessary computations during the surface extraction procedure
Tassin, Alan. "Modélisation tridimensionnelle d'impacts hydrodynamiques pour l'étude du tossage des bulbes d'étrave". Brest, 2010. http://www.theses.fr/2010BRES2029.
Texto completoThe present work deals with the modelling of water impacts in order to determine the hydrodynamic loads occurring during bulbous bow slamming. A three-dimensional model of water impact based on the Wagner theory has been developed. Such an approach is attractive, as it is accurate for blunt bodies and requires low computational resources. A new numerical method is proposed to solve the threedimensional Wagner problem by using the displacement potential approach and the Boundary Element Method. The hydrodynamic pressure is determined with the modified Logvinovich model. The proposed approach has been used to study several three-dimensional bodies. In addition, experimental tests have been carried out by using a hydraulic shock machine and CFD investigations have been made using a Finite Element software. A very good agreement between the three approaches has been observed. Furthermore, the efficiency of the proposed approach highlights the possibility of using it as a practical tool for preliminary design or optimization