Tesis sobre el tema "Pression de rayonnement acoustique"
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Margnat, Florent. "Méthode numérique hybride pour l'étude du rayonnement acoustique d'écoulements turbulents pariétaux". Poitiers, 2005. http://www.theses.fr/2005POIT2316.
Texto completoA hybrid approach is proposed for the prediction of wall-bounded flow noise. Aerodynamic data are computed through an incompressible direct numerical simulation. The no-slip condition is modelled by the virtual boudary method, especially tailored for complex geometries, and original in the field of aeroacoustics. 3D turbulent plane channel flow was simulated for validation, in particular for the pressure fluctuations. The process of vortex shedding by the shear layer generated at the leading edge of a blunt flat plate is analysed. For this configuration, the acoustic radiation is computed through the Curle's analogy, implemented via an advanced time algorithm. For a compact source, maximum emission is observed near 60° downstream, due to the volumic source terms, that are stronger than surfacic terms. This is also the case for a non-compact source, but the influence of retarded times enhances the longitudinal term
MONTETAGAUD, FABIENNE. "Modelisation de la propagation et du rayonnement acoustiques des entrees d'air de turboreacteurs". Le Mans, 1998. http://www.theses.fr/1998LEMA1004.
Texto completoLargeau, Jean-François. "Analyse expérimentale de la dynamique et du rayonnement acoustique d’un écoulement de marche montante". Poitiers, 2004. http://www.theses.fr/2004POIT2306.
Texto completoThe subject of this experimental study is the flow generated over a forward-facing step. The impact of several parameters (height of step and rate of flow) on the spatio-temporal flow organisation is investigated. The aim is also to clarify relationships between wall fluctuation pressure and the velocity field. Also, a model is designed and microphones probes are developed to investigated wall fluctuations pressures. Moreover, spatial flow organisation is examined with a Particle Image Velocimetry system for different configurations (height and flow rate). First the 2D hypothesis is improved (with wall flow visualisations experiments, hot-wire anemometry, wall pressure fluctuations probes). Moreover, spatial flow organisation is examined with a Particle Image Velocimetry system for different configurations (height and flow rate). The velocity field is mesurated simultaneously with the wall pressure fluctuations and acoustic pressure. Accordingly, the structure convection velocity, integrals flow scales and correlations between these different data are obtained overall the model. Finally, a Curle model computation is realised with experimental wall pressure fluctuations data and the estimated sound field is compared with acoustic measurements
Liu, Zubin. "Etude numérique et expérimentale des modes de rayonnement champ proche de structures vibrantes". Ecole centrale de Marseille, 2013. http://www.theses.fr/2013ECDM0012.
Texto completoHebri, Salem. "Études de la pression de radiation dans les interféromètres utilisés pour la détection des ondes gravitationnelles". Nice, 2007. http://www.theses.fr/2007NICE4103.
Texto completoThe Virgo detector is a Michelson interferometer with 3 km Fabry Perot cavities in the arms and using the power recycling technique. The main aim is the direct detection of gravitational waves emitted by astrophysical sources. The injection system is constituted essentially by a triangular 144 m long cavity with the middle mirror suspended called the Mode Cleaner, capable of selecting the TEM00 mode only. The suspended mirror is very light (360g), which can make it sensitive to the photon pressure. I developed some simulation codes for a triangular cavity with all controls identical to a real Virgo mode cleaner. These codes can be used for other studies. The first part of this thesis is dedicated to studying the effects of the radiation pressure on the mode cleaner for the lock acquisition, the optical angular spring etc. In the second part, I made the same simulation for studying the effect of the radiation pressure in 3 km long Virgo cavities, essentially on the optical angular spring, which can make problems for the automatic alignment on Virgo. Finally, I describe my participation to the Virgo commissioning, which primarily consists in working on control systems for the system of laser beam injection and their optimization
Almohamad, Samir. "Micro-manipulation de fluides miscibles et de fibres de collagène à l'aide de pinces acoustiques à faisceau unique". Electronic Thesis or Diss., Université de Lille (2022-....), 2024. http://www.theses.fr/2024ULILN038.
Texto completoUltrasound techniques have proven to be powerful tools for controlling dispersed immiscible droplets. By carefully shaping the acoustic field, these droplets can be sorted, divided, merged, selectively targeted, and repositioned with precision. Common methods include using standing waves to capture droplets at specific pressure nodes or antinodes, as well as employing traveling waves to move droplets along the path of wave propagation. Recent breakthroughs have led to the development of selective acoustic tweezers, which utilize focused beams or acoustic vortices for the precise manipulation of individual droplets. However, ultrasound-based manipulation has traditionally focused on immiscible fluids. Karlsen, Augustsson, and Bruus [Phys. Rev. Lett. 117, 114504 2016] suggested the possibility of manipulating miscible fluids with selective tweezers. However, their work was purely theoretical and no experimental demonstrations have been achieved so far. Such a demonstration is very challenging because of the weak acoustic contrast between miscible fluids and the diffusion process, progressively blurring the interface.This Ph.D. research experimentally demonstrates the possibility of patterning, trapping, and dislocating high-concentration miscible-fluid blobs (Ficoll) within a lower-concentration medium (water) using selective acoustic tweezers. It delves into the complex interactions between ultrasound waves and miscible fluids, with a particular focus on nonlinear acoustic effects such as acoustic radiation force and acoustic streaming and their influence on fluid behavior at microscales. The experimental setup integrates single-beam acoustical tweezers with microfluidic devices, allowing precise control and manipulation of fluids. The experimental results are compared with numerical simulations, resulting in good agreement between the two.We further explored the manipulation of other objects with low acoustic contrast: collagen fibers. Our preliminary results suggest the possibility of manipulating these fibers within a fluid medium. This noninvasive method has potential implications in tissue engineering and biomedical research
Skalli, Housseini Aniss. "Développement d'un outil de simulation basé sur le lancer de faisceaux pour la prédiction du bruit intérieur et du rayonnement extérieur des nacelles". Mémoire, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/6611.
Texto completoLindberg, Anders Sven Axel. "Airborne noise characterisation of a complex machine using a dummy source approach". Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0082/document.
Texto completoThe characterisation of vibrating sound sources is a challenge in noise and vibration engineering. In this thesis, an experimental approach to the characterisation of air-borne sound from a complex machine is investigated. A proper characterisation has to account for both radiation and diffraction phenomena in order to describe the sound source when inserted into an arbitrary space which enables prediction of sound pressure. A particular technique — a dummy source — has been conceived to deal with this problem. The dummy is a closed cabinet of similar size but much simpler shape than the complex machine, and it serves as a model of sound diffraction. The dummy is equipped with a flush-mounted array of loudspeaker drivers. The superposition of sound fields created by the individual drivers models sound radiation of the complex machine. This thesis introduces the concept of a dummy source and discusses three problems that need to be addressed for its practical application: (1) estimation of the transfer impedance of the space (the Green’s function), (2) the specification of the cabinet and the driver array, and (3) the estimation of the equivalent source strengths in terms of volume velocity. The approach is investigated via experimental and numerical case studies
Di, Pace Sibilla. "Vers l’observation du bruit quantique de la pression de radiation dans un interféromètre suspendu : l’expérience QuRaG". Thesis, Nice, 2014. http://www.theses.fr/2014NICE4108/document.
Texto completoThe existence of gravitational waves (GW) is one of the most interesting predictions of the theory of general relativity of Einstein. The experimental discovery of GW would be an important test of the theory itself. In addition, the detection of GW will open a new window of observation especially in those regions of the Universe inaccessible to electromagnetic observations. Interferometers, as Virgo are the most promising devices for the detection of GW. Currently, the sensitivity of these detectors is not yet sufficient to have a detection rate of few events/year. Therefore, an intense experimental program to improve the sensitivity is underway. Specifically, the sensitivity of the next generations of GW detectors, at low frequencies, will be limited by the effect of the radiation pressure (RP) on the suspended mirrors. This phenomenon not yet observed experimentally in the ground based GW detectors band, is currently the subject of a very active research field. My work presented here aims at building a detector for studying quantum effects of RP in GW detectors: the QuRaG experiment. It will consist of a suspended Michelson interferometer where each arm will be a high finesse Fabry-Pérot cavity, in which only the end mirror will be further suspended and then sensitive to the RP noise. During my PhD I have actively participated to the R&D of all QuRaG subsystems. Therefore, the work that I have done deals with various aspects of the project whose related problems belong to different domains of physics. My work described in this manuscript demonstrates that QuRaG is realizable and that it will be able to observe the RP noise in the expected frequency range
Degeorges, Jean-François. "Rayonnement acoustique des plaques en champ proche". Le Mans, 1988. http://www.theses.fr/1988LEMA1016.
Texto completoBeslin, Olivier. "Rayonnement et transparence acoustique des plaques trouées". Lyon, INSA, 1993. http://www.theses.fr/1993ISAL0025.
Texto completoThe acoustical radiation of holed plates is modelized by using a variational approach for the mechanical structure and an integral formulation of the pressure field (double layered potential). The uniqueness; of modal expansions due to hales presence is removed with a new concept of "ectoplasm". The program is validated regarding to a finite elements program in a first part and by comparing with experimental results; in a second part. This work generalize the integro-modal methods to complicated shape structures, and lead a way to the resolution of many industrial and building trade acoustical problems (double perforated plate), or musical application (simulation of a guitar)
Degeorges, Jean-François. "Rayonnement acoustique des plaques en champ proche". Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376130547.
Texto completoMillot, Pascal. "Rayonnement acoustique de plaques couplées dans une cavité". Lyon, INSA, 1987. http://www.theses.fr/1987ISAL0033.
Texto completoMillot, Pascal. "Rayonnement acoustique de plaques couplées dans une cavité". Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37608016p.
Texto completoIssenmann, B. "Déformations d'interfaces fluides par la pression de radiation acoustique". Phd thesis, Université Sciences et Technologies - Bordeaux I, 2007. http://tel.archives-ouvertes.fr/tel-00283449.
Texto completoBoudreau, Alex. "Contrôle actif du bruit acoustique des ventilateurs haute pression". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0034/MQ67250.pdf.
Texto completoBoudreau, Alex. "Contrôle actif du bruit acoustique des ventilateurs haute pression". Mémoire, Université de Sherbrooke, 1998. http://savoirs.usherbrooke.ca/handle/11143/1076.
Texto completoIssenmann, Bruno. "Déformations d'interfaces fluides par la pression de radiation acoustique". Bordeaux 1, 2007. http://www.theses.fr/2007BOR13505.
Texto completoBoudreau, Alex. "Contrôle actif du bruit acoustique des ventilateurs haute pression". Sherbrooke : Université de Sherbrooke, 1999.
Buscar texto completoDuprey, 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
Mattei, Pierre-Olivier. "Rayonnement acoustique des structures : méthodes d'équations intégrales de frontières". Aix-Marseille 2, 1991. http://www.theses.fr/1991AIX22047.
Texto completoQuaegebeur, Nicolas. "Vibrations non linéaires et rayonnement acoustique de structures minces de type haut-parleur". Palaiseau, Ecole polytechnique, 2007. http://www.theses.fr/2007EPXX0021.
Texto completoSchevin, Olivier. "Contribution à l'étude des modes de rayonnement acoustique d'une structure /". Lausanne, 2001. http://library.epfl.ch/theses/?nr=2392.
Texto completoAublin, Benoit. "Rayonnement et diffraction acoustique par un guide ouvert semi-infini". Compiègne, 1996. http://www.theses.fr/1996COMPD969.
Texto completoFei, Binjun. "Comportement dynamique et rayonnement acoustique d'une culasse de moteur diesel". Paris, CNAM, 1986. http://www.theses.fr/1986CNAM0076.
Texto completoCORDONNIER, CLOAREC PASCALE. "Contribution à l'étude du rayonnement acoustique de parois métalliques nervurées". Toulouse 3, 1989. http://www.theses.fr/1989TOU30056.
Texto completoMartinet, Maurice. "Analyse multirésolution en ondelettes du rayonnement acoustique des structures planes". Lyon, INSA, 2001. http://theses.insa-lyon.fr/publication/2001ISAL0082/these.pdf.
Texto completoThe acoustic radiation of a vibrating structure is a complex phenomenon and generally, the only interest to be taken in is the field of pressure emitted far from the object. The undulatory analysis shows that only a part of the vibratory field is at the origin of the noise emitted in a far field concerning a finite baffled plane structure. Research were about the multi-resolution analysis in wavelets (AMRO), so as to characterize this vibratory field which is at the origin of the sound nuisance. Wavelets allow to obtain equivalent acoustic sources thanks to their filtering capacity in the space reserved to wave-numbers. Their natures as well as their localizations then depend on both the resolution of reconstruction and the analysing wavelet family. The application of AMRO allowed to find again and to quantify the empiric notions of radiation by corners or by edges within the radiation of the plate modes. The obtained equivalent acoustic sources near quite satisfactorily the radiated pressure in a far field when they are on a plate submitted to different types of excitations. They are mainly located at the periphery and the point of application in the case of a punctual mechanic force. Source lines can be obtained according to the incidence angle for an excitation by plane waves. An experimentation on a simple structure allowed to get the radiated acoustic pressure through equivalent sources stemmed from AMRO. This work opens perspectives to the active control of the acoustic radiation
Martinet, Maurice Guyader Jean-Louis. "Analyse multirésolution en ondelettes du rayonnement acoustique des structures planes". Villeurbanne : Doc'INSA, 2005. http://docinsa.insa-lyon.fr/these/pont.php?id=martinet.
Texto completoMas, David. "Rayonnement acoustique d'une cavité rectangulaire soumise à un écoulement turbulent". Grenoble INPG, 2000. https://theses.hal.science/tel-00278358.
Texto completoFlows over rectangular cavities exhibit various steady and unsteady phenomena, and are of concern in several engineering areas. When the incident flow is turbulent, high acoustic radiations are emitted. To evaluate the acoustic power radiated in the far field, a two-steps procedure is developed. First, the unsteady, incompressible, high Reynolds number flow past a cavity is numerically investigated. The hydrodynamical 3D models which are used are based on standard Reynolds-averaged Navier-Stokes equations closed by some simple turbulence closure models. On another side, experiments are performed in a large water tunnel for different length to depth ratios; flow visualization and fluctuating surface pressure measurements are made to check numerical results which reveal some deficiencies. Morover, the extent of both numerical and experimental results combined to produce consistent input data for the ensuing acoustic model. Secondly, a simple model, based on the Lighthill's acoustic analogy, incorporates the later data, to predict the amplitude and the frequencies of the far field noise. Measurements of the far field sound pressure level in a wind tunnel are also made at subsonic speed. A good agreement between the computed acoustic power in the far field and experimental data is shown. As an interesting by-product of the hydrodynamical study consists in a refined classification of flow structures in the cavity when length-to-depth ratio increases. Three different flow configurations are observed. A quasi-2D flow is observed for a squared cavity. A transitional 3D flow characterized by spanwise undulation of the main recirculating eddy is clearly shown for a length-to-depth ratio about 1,5. For a length-to-depth ratio above 2, the main recirculating eddy which is close to the downstream face of the cavity is purely 2D
Lagarrigue, Olivier. "Contrôle actif structural du rayonnement de plaque". Aix-Marseille 2, 1994. http://www.theses.fr/1994AIX22069.
Texto completoRobin, Olivier. "Reproduction de champs de pression acoustique aléatoires sur des surfaces planes". Thèse, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6140.
Texto completoGuillaussier, Philippe. "Étude du comportement acoustique des nouveaux matériaux piézoélectriques sous pression hydrostatique". Lille 1, 1990. http://www.theses.fr/1990LIL10123.
Texto completoMargnat, Florent. "METHODE NUMERIQUE HYBRIDE POUR L'ETUDE DU RAYONNEMENT ACOUSTIQUE D'ECOULEMENTS TURBULENTS PARIETAUX". Phd thesis, Université de Poitiers, 2005. http://tel.archives-ouvertes.fr/tel-00012176.
Texto completoPolonio, Franck. "Calcul du rayonnement acoustique d'une structure d'épaisseur moyenne comportant des ouvertures". Clermont-Ferrand 2, 2002. http://www.theses.fr/2002CLF21349.
Texto completoBailly, Christophe. "Modélisation du rayonnement acoustique des écoulements turbulents libres subsoniques et supersoniques". Châtenay-Malabry, Ecole centrale de Paris, 1994. http://www.theses.fr/1994ECAP0338.
Texto completoOuelaa, Nouredine. "Rayonnement acoustique des conduits cylindriques finis, parcourus par un écoulement uniforme". Lyon, INSA, 1993. http://www.theses.fr/1993ISAL0075.
Texto completoAn analytical of the modelisation of the acoustic radiation from a finite cylindrical shell with infinite rigid extensions is presented9 The shell is immersed in an infinite surrounding fluid at rest and contains flowing fluid. The shell is excited either by an harmonic driving force or by internal acoustic sources. In this study the theory and the main original results on the internal radiation impedances, the influence of the flowing fluid and the influence of the nature of fluid (heavy and/or light) on the acoustic radiated power in both medium exterior and interior are presented
Maury, Cédric. "Rayonnement acoustique de structures vibrantes : études en régime temporel et fréquentiel". Aix-Marseille 2, 1999. http://www.theses.fr/1999AIX22050.
Texto completoOddo, Lionel. "Prévision du rayonnement acoustique des structures complexes et identification des sources". Lyon, INSA, 1999. http://www.theses.fr/1999ISAL0057.
Texto completoThe purpose of the study is to use two different approaches to model the vibro-acoustic behaviour of a complex structure: an analytical modeling and a systemic modeling. Analytical modeling dealt with the problem of the acoustic radiation of a cylindrical shell coupled to internal mechanical structures. Several examples resulting from numerical simulations and experimentation highlighted the phenomenon of "frequential smoothing" of the vibro-acoustic response of the shell. However, this phenomenon requires severe conditions on the internal mechanical structures: they must be of strong modal density and adapted in impedance with the shell. If these conditions are observed, then it is possible to consider the apparent damping of the shell, from the S. E. A. Formulation of the coupling loss coupling. Systemic modeling, by the use of the neural networks, was applied to the problem of the localization of the efforts upon a structure. For that, a neural network is built from the knowledge of the vibratory field of the structure, as well as position of the effort. The network is then able to locate an unknown effort, according to the measured or calculated fields vibratory. It was shown that the quality of the results provided by the neural networks strongly depended on a criterion in wavelength at the distance between the efforts chosen for the training of the network
Boissinot, Philippe. "Impédance acoustique de rayonnement, impédance mutuelle, et application aux directives d'antenne". Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37612035q.
Texto completoGuérin, Sébastien. "Réduction de sons auto-entretenus par effet Coanda sur des jets auxilliaires". La Rochelle, 2001. http://www.theses.fr/2001LAROS070.
Texto completoThe present study deals with the reduction of the self-sustained tones (the whistling) produced by a low Mach number air flow crossing two rigid baffles in tandem inside a duct. These tones have a single well defined frequency matching the longitudinal acoustic resonance of the pipe and have a high amplitude. Typically, their sound pressure level attains 130 to 140 dB (re 20 mPa) when the ratio between the baffle spacing and the diameter of their aperture belongs to the range [0. 4; 3] and the Reynolds number varies between 104 and 105
Billon, Alexis. "Etude expérimentale des sons auto-entretenus produits par un jet issu d'un conduit et heurtant une plaque fendue". La Rochelle, 2003. http://www.theses.fr/2003LAROS103.
Texto completoThe production of self-sustained tones (up to 125 dB) by a low Mach number free plane jet impinging on a slotted plate, known as slot-tone, is experimentally studied. For all geometries of the slot's edge tested, the tones are generated from 6 m/s and when a resonant mode of the duct from which the jet flows out is excited. The Strouhal number associated with the tones fundamental frequency describes stages. These one are linked to the number of vortices present, with vortex pairing possibilities. On the other hand, the frequency domain of the fundamental is defined by the two instability modes of the jet. If the edge of the slot is beveled and if this one is placed backwards to the flow, the tones occurs at a lower speed (3. 5 m/s) as soon as the jet becomes turbulent, and the excitation of an acoustic resonator is then not necessary
Toumi, Arezki. "Étude des résonances acoustiques dans une lampe à décharge haute pression à enveloppe céramique". Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1566/.
Texto completoNowadays, the available commercial electronic ballasts used to supply HID lamps usually operate at low frequency (several hundred hertz) square waves and have the disadvantage to be bulky and complex to implement, so expensive. Thus, to reduce their cost, it is necessary to supply the lamp at high frequency, which enable, in addition, to reduce the size of the ballast (-40% to 60%), its weight (-10% to 30%) and its electrical power consumption (-10% to -15%). However, on lamps operating at high frequency, we can see the occurrence of instabilities inducing its malfunction and, in some cases, its destruction. This phenomenon known as acoustic resonances is due to the generation of acoustic waves which propagate towards the lamp walls where they are damped and reflected. When the incident and reflected waves interact, standing waves are generated and may interact with the electric discharge causing the lamp dysfunction. Despite the many studies on this subject, the physical understanding of this phenomenon remains incomplete. The way in which the acoustic waves interact with the electrical discharge is poorly understood and current numerical models, including the influence of acoustic resonances, enable only to locate the frequencies corresponding to eigenmodes of the lamp without providing explanation of the phenomenon. This thesis was devoted to the realization of a numerical model of a discharge lamp taking into account this interaction in order to improve the physical understanding of acoustical resonances and their impact on the arc instabilities of the lamp according electrical signal frequency. Using the results obtained with this model, we are able to explain the way in which the acoustic resonances are generated and how they interact with the lamp
Martin, Seigle Sabine. "Rayonnement acoustique de coques cylindriques immergées, couplées à un fluide interne léger". Aix-Marseille 2, 1997. http://www.theses.fr/1997AIX22077.
Texto completoRodrigues, Dominique. "Méthode de réciprocité : caractérisation de petits composants acoustiques, étalonnage des microphones en pression et en champ libre". Phd thesis, Université du Maine, 2008. http://tel.archives-ouvertes.fr/tel-00349206.
Texto completoCe propos met en cause la précision de l'étalonnage des étalons de mesure de pressions acoustiques et l'insuffisance des réglages d'appareils médicaux largement utilisés. Les enjeux pratiques, techniques et scientifiques ont donc leur importance et les études à mener comportent des exigences qui nécessitent des recherches approfondies. C'est ainsi que les thèmes abordés font appel ici à la méthode de la réciprocité en cavité et en champ libre.
Dans la première partie du travail, l'objectif recherché est d'adapter et d'améliorer la méthode de réciprocité en cavité. L'adaptation de cette méthode conduit à une technique de mesure d'impédances d'entrée de petits éléments acoustiques, tels que des tubes, fentes, cavités (utilisés dans l'oreille artificielle). L'amélioration des incertitudes de mesure des efficacités recherchée pour les hautes fréquences a conduit à proposer une modélisation améliorée d'un microphone ainsi que du dispositif d'étalonnage dans sa globalité de manière à étudier l'influence des modes radiaux dans la cavité sur les résultats de l'étalonnage.
La deuxième partie de ce travail trouve son origine dans une comparaison clé à l'échelle internationale portant sur les techniques d'étalonnage des microphones en champ libre. Cette comparaison clé a nécessité une refonte complète du dispositif expérimental du LNE, des techniques d'acquisitions et des méthodes de filtrage des perturbations liées aux faibles niveaux acoustiques mis en jeu. Ce travail a conduit à entreprendre des études plus approfondies sur les plans analytique et expérimental du concept de centre acoustique d'un microphone.
Certains résultats obtenus posent les bases des travaux futurs qui devraient permettre de poursuivre la modélisation pour réduire les incertitudes mais également pour prévoir la mise en oeuvre des méthodes adaptées à la métrologie des capteurs du futur qui seront fabriqués par des procédés relevant des microtechnologies.
Pensec, Ronan. "Contrôle non destructif par émission acoustique des aciers pour équipements sous pression". Compiègne, 2000. http://www.theses.fr/2000COMP1297.
Texto completoBertin, Nicolas. "Déformations d'interfaces liquides guidantes par la pression de radiation acoustique et optique". Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14266/document.
Texto completoAcoustic radiation pressure allows us to remotely create and manipulate liquid objets. Using a highly focused transducer, which emitted field is studied, we can create large aspect ratio and complex liquid interface deformations. This fundamental research aims at understanding these various objects. For this purpose, we developed a theoretical model taking into account the coupling between the wave propagation and the deformation of the interface. This model allows us to predict the characteristics of liquid columns both formed and stabilized by the acoustic radiation pressure. A study of acoustic liquid jets is performed as well. Moreover, we characterize finger-shaped andpacifier-shaped objects as piles of acoustic waveguides. The acoustic wave creates a liquidobject self-adapted to its propagation. For each of these studies, we compare deformationsobtained via the acoustic radiation pressure and the electromagnetic radiation pressurefrom a continuous laser beam
Carpreau, Jean-Michel. "Contrôle des capacités à pression en acier inoxydable austénitique par émission acoustique". Compiègne, 1992. http://www.theses.fr/1992COMPD489.
Texto completoSOTO, NICOLAS ALBERTO. "Etude et realisation de haut-parleurs piezo-electriques a rayonnement lateral". Le Mans, 1997. http://www.theses.fr/1997LEMA1023.
Texto completoDe, Man Pierre. "Contrôle actif du rayonnement acoustique des plaques: une approche à faible autorité". Doctoral thesis, Universite Libre de Bruxelles, 2004. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211180.
Texto completoLe contrôle actif à faible autorité, pour lequel le Laboratoire de Structures Actives a développé une expertise dans le domaine de l'amortissement et du contrôle actif des vibrations, est une solution attractive par sa simplicité de mise en oeuvre. Le plus souvent implémenté sous la forme d'un contrôle décentralisé constitué de boucles indépendantes, le contrôle à faible autorité bénéficie de certaines garanties de stabilité et de robustesse.
Bien que notre stratégie de contrôle puisse s'appliquer à n'importe quel type de plaque, l'application considérée dans ce travail a été motivée par le contexte socio-économique actuel en rapport avec les nuisances acoustiques. Il était en effet intéressant d'évaluer la stratégie de contrôle pour le problème de la transmission acoustique d'un vitrage. La stratégie de contrôle se divise en deux étapes. Tout d'abord le développement d'un capteur unique destiné à fournir une mesure représentative du bruit rayonné par une plaque en basse fréquence. Deux capteurs de vitesse volumétrique (l'un discret, l'autre distribué) ont ainsi été développés et évalués expérimentalement.
Ensuite, une procédure d'optimisation de l'emplacement d'un ensemble d'actionneurs pilotés en parallèle est proposée. L'objectif de cette phase d'optimisation est de forcer la réponse fréquentielle du système à posséder les propriétés d'un système colocalisé. La stratégie de contrôle est ensuite évaluée sur deux structures expérimentales.
/ This thesis is concerned with a low authority active control strategy applied to the sound radiation control of a baffled plate. Since the development of active control ,numerous researchers have studied its application to acoustical or vibroacoustical problems using either the modern control theory or other methods based rather on the understanding of the physics of the problem. Vibroacoustical active control has lead to the definition of radiation modes allowing to describe the radiated sound of a plate in an appropriate manner for active control purposes.
Low autorithy control (LAC), for which the Active Structures Laboratory has gained an expertise for active vibration control applications is an interesting solution for its implementation simplicity. Most of the time it consists of several decentralized control loops, and benefits from guaranteed stability and robustness properties. Although our control strategy can be applied to any kind of plates, the application considered here has been motivated by the present socio-economical context related to noise annoyances. The active control strategy has been applied the problem of the sound transmission loss of glass plates (windows). This strategy is in two steps :first a volume velocity sensor is developed as to give a measure representative of the radiated sound at low frequencies.
Two sensors have been developed (one discrete and one distributed) and experimentally tested. Next, an optimisation strategy is proposed which allow to locate on the plate a set of several actuators driven in parallel. The goal of this optimisation task is to obtain an open-loop frequency response which behave like a collocated system. The control strategy is finally evaluated on two plate structures.
Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished
Faure, 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.
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