Literatura académica sobre el tema "Rayonnement acoustique d'un turboréacteur"
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Artículos de revistas sobre el tema "Rayonnement acoustique d'un turboréacteur"
BERGE, D. y J. M. CAILLEAU. "Simulation numérique du contrôle acoustique actif appliqué au bruit d'un turboréacteur". Le Journal de Physique IV 04, n.º C5 (mayo de 1994): C5–199—C5–202. http://dx.doi.org/10.1051/jp4:1994538.
Texto completoLAULAGNET, B. y J. L. GUYADER. "RAYONNEMENT ACOUSTIQUE DES COQUES CYLINDRIQUES, MUNIES D'UN MATÉRIAU DE MASQUAGE". Le Journal de Physique Colloques 51, n.º C3 (septiembre de 1990): C3–135—C3–145. http://dx.doi.org/10.1051/jphyscol:1990315.
Texto completoGloerfelt, Xavier, Christophe Bailly y Daniel Juvé. "Calcul direct du rayonnement acoustique d'un écoulement affleurant une cavité". Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics 328, n.º 8 (agosto de 2000): 625–31. http://dx.doi.org/10.1016/s1620-7742(00)00012-x.
Texto completoTahar, Mabrouk Ben y Jean Paul Dias. "Propagation et rayonnement acoustique en présence d'un écoulement non uniforme par une méthode de couplage FEM/BEM". Revue Européenne des Éléments Finis 8, n.º 5-6 (enero de 1999): 497–524. http://dx.doi.org/10.1080/12506559.1999.10511395.
Texto completoLe Moyne, Sylvie y Jean-Louis Tébec. "Influence d'une erreur de prévision des fréquences propres sur les résultats d'un calcul de rayonnement acoustique par méthode éléments de frontière". Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Astronomy 328, n.º 4 (abril de 2000): 329–33. http://dx.doi.org/10.1016/s1287-4620(00)00137-x.
Texto completoTesis sobre el tema "Rayonnement acoustique d'un turboréacteur"
Duprey, Stefan. "Etude mathématique et numérique du rayonnement acoustique d'un turboréacteur". Nancy 1, 2006. https://tel.archives-ouvertes.fr/tel-00145205.
Texto completoThis thesis deals with the industrial problem of modelisation and numerical simulation of the acoustic radiation from fan duct air entry. The physical hypothesis subsequent to the industrial framework give way to a simplified model of linear acoustic propagation upon a non linear potential flow. Engine modal noise source modelisation requires acoustic boundary conditions through a Dirichlet-Neumann operator. Existence and uniqueness of the global mathematical problem (a convected Sommerfeld condition is added) of the potential and local perturbation from a uniform flow are prooved. A discrete coupling between the volumic acoustic potential (finite volumic elements) and its elliptic normal derivate (boundary finite element) through an integral equation is exhibed. Computing code is validated analytically and comparatively. Original results are described and prove the necessity to consider the nonlinearity of the flow by differences greater than 5 dBs in the far field acoustic diagrams. Optimal positionning of the radiating surface and the plugability of the fast multipole method make this coupling unmissable. Simplified potential-linear model, even if its range of validity is restricted to the fan duct air entry, gets his whole interest as a brick in a global domain decomposition code. By the way, lets mention the achievement of a natural axisymetric finite element and an alternative method to the calculus of the non linear flow by a fixed point method
Duprey, Stefan. "Etude mathématique et numérique de la propagation acoustique d'un turboréacteur". Phd thesis, Université Henri Poincaré - Nancy I, 2006. http://tel.archives-ouvertes.fr/tel-00145205.
Texto completola simulation numérique du rayonnement acoustique à l'entrée d'air des nacelles
d'Airbus. Les hypothèses physiques subséquentes au contexte industriel
précis conduisent à un modèle simplifié de propagation acoustique linéaire sur
un écoulement porteur potentiel et non-linéaire. La modélisation de la source
modale de bruit du moteur se traduit par une condition de bord exprimée par
un opérateur Dirichlet-Neumann. L'existence et l'unicité du problème mathématique
général (auquel on a rajouté une condition de Sommerfeld convectée)
de la perturbation potentielle et locale autour d'un écoulement uniforme sont
démontrées. Un couplage discret alliant le potentiel acoustique (éléments finis
de volume) et sa dérivée conormale de bord (éléments finis de frontière) par une
équation intégrale est proposé. Le code informatique est validé analytiquement
et comparativement. Les résultats originaux prouvent la nécessité de la prise en
compte des non-linéarités de l'écoulement par des différences de plus de 5 décibels
en champ lointain. Le positionnement optimal de la surface rayonnante et
la possibilité d'adaptation de la méthode multipôle rapide rendent ce couplage
incontournable. Le modèle simplifié potentiel-linéaire, même si il n'est a priori
apte qu'à traiter l'entrée d'air, trouve toute sa justification en tant que brique
d'un code global basé sur la décomposition de domaine. Finalement, soulignons
l'avènement d'un élément fini axisymétrique naturel et d'une alternative originale
de calcul de l'écoulement non-linéaire par une méthode de point fixe.
Marchner, Philippe. "Non-reflecting boundary conditions and domain decomposition methods for industrial flow acoustics". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0094.
Texto completoThis PhD project is devoted to non-overlapping Schwarz domain decomposition methods for the resolution of high frequency flow acoustics problems of industrial relevance. Time-harmonic solvers are difficult to parallelize due to their high-oscillatory behaviour, and current solvers quickly reach an upper frequency limit dictated by the available computer memory. Non-overlapping Schwarz methods split the domain into subdomains at the continuous level and provide a suitable setting for distributed memory parallelization. The problem is solved iteratively on the interface unknowns, where the keystone for quick convergence relies on appropriate transmission conditions. The first part of this thesis is devoted to the design of transmission operators tailored to convected and heterogeneous time-harmonic wave propagation. To this end we study two non-reflecting boundary techniques that provide local approximations to the Dirichlet-to-Neumann operator. On the one hand, Absorbing Boundary Conditions are designed based on microlocal analysis and pseudodifferential calculus. On the other hand, the convected acoustic stability issue is addressed for Perfectly Matched Layers in convex domains with Lorentz transformation. The second part of this thesis describes how to adapt a generic domain decomposition framework to flow acoustics, and applies the newly designed transmission conditions to simple academic problems. We explain the relation between the non-overlapping Schwarz formulation and an algebraic block LU factorization of the problem. Finally we propose a parallel implementation of the method and show the benefit of the approach for the three-dimensional noise radiation of a high by-pass ratio turbofan engine intake
Lidoine, Stéphane. "Approches théoriques du problème du rayonnement acoustique par une entrée d'air de turboréacteur : Comparaisons entre différentes méthodes analytiques et numériques". Ecully, Ecole centrale de Lyon, 2002. http://www.theses.fr/2002ECDL0029.
Texto completoFaure, Baldrik. "Caractérisation du rayonnement acoustique d'un rail à l'aide d'un réseau de microphones". Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00721959.
Texto completoDruon, Yann. "Etude de la propagation guidée et du rayonnement acoustiques par les conduits d'éjection de turboréacteur : Modélisations analytiques et numériques". Ecully, Ecole centrale de Lyon, 2006. http://www.theses.fr/2006ECDL0002.
Texto completoThis work deals with the modeling of the acoustic propagation inside turbofan exhaust ducts and the corresponding radiation to the outside. The main objectives are, first, to develop analytical methods, enabling fast and flexible simulations of the problem, and second, to assess the relevance of different numerical methods, now indispensable to account for more realistic geometries and aerodynamic conditions. The study is performed following a progressive process, beginning with simplified configurations to integrate the elements of physical complexity one by one (presence of acoustic liners, realistic geometry, uniform and non-uniform mean flows…). At each stage, the results of the different methods are compared and the influence of the principal parameters is analyzed. The reference solution is given here by an analytical method based on the modal theory for annular ducts with constant cross section. The far field radiation is calculated, in the case of a hub truncated at the exit plane, using the flanged duct approximation, and for an infinite hub, with the aid of the Wiener-Hopf technique. In this last model, the possibility of vortex shedding from the duct trailing edge is included by application (or not) of a Kutta condition. At low frequency, and in the absence of mean flow, the Boundary and the Finite Element Methods (BEM and FEM) give the same results. The comparisons with measurements are also very good, confirming the relevance of the theoretical models. In the presence of a uniform mean flow, the BEM and the FEM respectively tend to the analytical solutions obtained with and without the Kutta condition imposed at the edge. The particular behavior associated to each method is thought to be related to the acoustic variable considered in the codes, i. E. Acoustic pressure or potential. At high frequency, the results of the Gaussian Beam Summation approach are found to be unsatisfactory, probably because of the absence of any diffraction model in the current code formulation. Several geometrical factors influence the acoustic propagation in the secondary exhaust duct (By-Pass). The most critical point lies in the presence of two bifurcations that induce modal redistributions increasing with the rotation of the incident wave inside the duct. An analytical model for sound propagation in a bifurcated duct is presented and validated by comparison with BEM results. Outside the ducts, the influence of the pylon and the after-body real geometry on the radiation to the ground seems to be more limited. Conversely, the effect of shear layers generated at the duct trailing edges is significant. In spite of theoretical restrictions, the waves refraction due to flow mismatches across a vortex sheet (Munt’s model) seems to be relatively well predicted by the FEM potential formulation. The impact of density or temperature gradients, however, is not well reproduced
Dérogis, Philippe. "Analyse des vibrations et du rayonnement de la table d'harmonie d'un piano droit et conception d'un système de reproduction du champ acoustique". Le Mans, 1997. http://www.theses.fr/1997LEMA1012.
Texto completoHilbrunner, Olivier. "Développement et optimisation d'un système de contrôle actif pour les absorbants acoustiques hybrides". Ecully, Ecole centrale de Lyon, 2003. http://bibli.ec-lyon.fr/exl-doc/ohilbrunner.pdf.
Texto completoIn order to increase the frequency band of absorption of usual porous materials, the "Centre Acoustique du LMFA" works on the design of hybrid materials using passive and active absorption. The basic principle consists in vanishing by active control the pressure at the rear face of the material, with well-suited characteristics, to achieve a maximum absorption. This thesis deals with the optimisation of the active part, which means a design of a powerful secondary source, including vibroacoustic coupling from the cavities and the effect of wiremesh and the implementation of a digital feedback diagonalised IMC control algorithm. An experiment using four independent cells proves the good functioning of the controller in a duct with flow : very important noise reductions were achieved in the low frequency band
Laulagnet, Bernard. "Rayonnement acoustique des coques cylindriques, finies raidies, revêtues d'un matériau de masquage". Lyon, INSA, 1989. http://www.theses.fr/1989ISAL0035.
Texto completoRIFAI, SAID. "Etude du rayonnement acoustique d'un obstacle cylindrique place dans un ecoulement d'air subsonique". Poitiers, 1989. http://www.theses.fr/1989POIT2280.
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