@prefix dcat: <http://www.w3.org/ns/dcat#> .
@prefix dct: <http://purl.org/dc/terms/> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix vcard: <http://www.w3.org/2006/vcard/ns#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

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    dct:description """
              This work deals with the acoustic scattering by a random distribution of cylindrical shells in a fluid. This study<br />has three parts. The first one is about a limited number of shells. A resonant coupling is shown. This couple<br />induces a split of the A-wave (Scholte-Stoneley wave) resonances. These splits are experimentally validated.<br />The second part presents two effective media theories: Waterman and Truell's and the Fikioris and Waterman's<br />one. They consist in the analytic averaging of the scattered field with the positions of shells. The average wave<br />obtained is called the effective or coherent wave. The major difference between these theories is that Fikioris and<br />Waterman take into account the size of the shells whereas, in the Waterman and Truell theory, the radius of the<br />shells tends towards zero. These two theories allow the computation of an effective wave number. The influence<br />of the resonances of one shell is seen on the effective phase velocity and on the effective attenuation. The results<br />of these two theories are compared with the ones of a third theory: the one of Foldy. All these theories give<br />similar results for weak concentrations, but, for strong concentrations, the results of the theory of Fikioris and<br />Waterman differ from the others. The study of a slab-like region with randomly placed shells leads to the<br />determination of a reflection and a transmission coefficient. These are similar to the ones obtained by<br />considering a fluid slab. The analogy between the inhomogeneous medium and a viscous fluid is possible. The<br />experimental study of such a medium gives good results for the effective attenuation. The last part deals with<br />inhomogeneous media with the shells replaced by a set of two shells close enough to produce resonant coupling.<br />In this case, an effective wave number is obtained with the Fikioris and Waterman theory. The reflection and<br />transmission coefficients can be expressed as the ones of a fictitious fluid-like slab for which the phase velocity<br />and the attenuation would be dependent of the direction of propagation.
            """ ;
    dct:identifier "tel-00086985" ;
    dct:issued "2026-05-09T11:45:44.799724"^^xsd:dateTime ;
    dct:language "fr" ;
    dct:modified "2026-05-09T11:45:44.799728"^^xsd:dateTime ;
    dct:publisher <https://rec.harvest-normandie.data4citizen.com/organization/cce9db95-46d9-4dc2-84b6-764215d0a002> ;
    dct:title "Multiple scattering by immersed elastic shells.<br />Propagation of coherent waves and resonant interactions." ;
    dcat:contactPoint [ a vcard:Organization ;
            vcard:fn "CCSD" ] ;
    dcat:distribution <https://rec.harvest-normandie.data4citizen.com/dataset/oai-hal-tel-00086985v1/resource/9da35a01-9db6-48ca-868e-e67454a234d8> ;
    dcat:keyword "acoustic-scattering",
        "anisotropie",
        "anisotropy",
        "coherent-wave",
        "diffusion-acoustique",
        "effective-media",
        "infoeu-reposemanticsdoctoralthesis",
        "milieu-effectif",
        "multi-diffusion",
        "multiple-scattering",
        "onde-coherente",
        "physmecaacouphysics-physicsmechanics-physicsacoustics-physicsclass-ph",
        "resonances",
        "theses" ;
    dcat:landingPage <https://theses.hal.science/tel-00086985> .

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    dct:format "HTML" ;
    dct:issued "2026-05-09T11:45:44.824031"^^xsd:dateTime ;
    dct:modified "2026-05-09T11:45:44.774726"^^xsd:dateTime ;
    dct:title "Multiple scattering by immersed elastic shells.<br />Propagation of coherent waves and resonant interactions." ;
    dcat:accessURL <https://theses.hal.science/tel-00086985> .

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