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1دورية أكاديمية
المؤلفون: Masson, Yder, Lyu, Chao, Moczo, Peter, Capdeville, Yann, Romanowicz, Barbara, Virieux, Jean
المساهمون: Université de Pau et des Pays de l'Adour (UPPA), Institute of Geology and Geophysics Beijing (IGG), Chinese Academy of Sciences Beijing (CAS), Comenius University in Bratislava, Laboratoire de Planétologie et Géosciences UMR_C 6112 (LPG), Le Mans Université (UM)-Université d'Angers (UA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Collège de France (CdF (institution)), Department of Earth and Planetary Science UC Berkeley (EPS), University of California Berkeley (UC Berkeley), University of California (UC)-University of California (UC), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement IRD : UR219-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 )
المصدر: ISSN: 0956-540X.
مصطلحات موضوعية: Computational seismology, Numerical modelling, Wave propagation, Numerical solutions, Seismic anisotropy, Structure of the Earth, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]
الوصف: International audience ; We present a time-domain distributional finite-difference scheme based on the Lebedev staggered grid for the numerical simulation of wave propagation in acoustic and elastic media. The central aspect of the proposed method is the representation of the stresses and displacements with different sets of B-splines functions organized according to the staggered grid. The distributional finite-difference approach allows domain-decomposition, heterogeneity of the medium, curvilinear mesh, anisotropy, non-conformal interfaces, discontinuous grid, and fluid-solid interfaces. Numerical examples show that the proposed scheme is suitable to model wave propagation through the Earth, where sharp interfaces separate large, relatively homogeneous layers. A few domains or elements are sufficient to represent the Earth’s internal structure without relying on advanced meshing techniques. We compare seismograms obtained with the proposed scheme and the spectral element method, and we show that our approach offers superior accuracy, reduced memory usage, and comparable efficiency.
العلاقة: hal-04464171; https://hal.science/hal-04464171Test; https://hal.science/hal-04464171/documentTest; https://hal.science/hal-04464171/file/Masson_et_al_GJI_2024.pdfTest
الإتاحة: https://doi.org/10.1093/gji/ggae025Test
https://hal.science/hal-04464171Test
https://hal.science/hal-04464171/documentTest
https://hal.science/hal-04464171/file/Masson_et_al_GJI_2024.pdfTest -
2دورية أكاديمية
المؤلفون: Cocquet, Pierre-Henri, Gander, Martin, J
المساهمون: Laboratoire des Sciences de l'Ingénieur Appliquées à la Mécanique et au génie Electrique (SIAME), Université de Pau et des Pays de l'Adour (UPPA), Section de mathématiques Genève, Université de Genève = University of Geneva (UNIGE)
المصدر: ISSN: 1064-8275 ; SIAM Journal on Scientific Computing ; https://hal.science/hal-03837707Test ; SIAM Journal on Scientific Computing, 2024, 46 (2), pp.A670-A696. ⟨10.1137/22M1531142⟩.
مصطلحات موضوعية: Frequency-Domain wave propagation, Finite difference method, Helmholtz equation, Numerical dispersion, Asymptotic dispersion correction, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA]
الوصف: International audience ; Most numerical approximations of frequency-domain wave propagation problemssuffer from the so-called dispersion error, which is the fact that plane waves at the discrete leveloscillate at a frequency different from the continuous one. In this paper, we introduce a new techniqueto reduce the dispersion error in general Finite Difference (FD) schemes for frequency-domainwave propagation using the Helmholtz equation as guiding example. Our method is based on theintroduction of a shifted wavenumber in the FD stencil which we use to reduce the numerical dispersionfor large enough numbers of grid points per wavelength (or for small enough meshsize), andthus we call the method asymptotic dispersion correction. The advantage of this technique is thatthe asymptotically optimal shift can be determined in closed form by computing the extrema of afunction over a compact set. For 1d Helmholtz equations, we prove that the standard 3-point stencilwith shifted wavenumber does not have any dispersion error, and that the so-called pollution effect iscompletely suppressed. For higher dimensional Helmholtz problems, we give easy to use closed formformulas for the asymptotically optimal shift associated to the second order 5-point scheme and asixth-order 9-point scheme in 2d, and the 7-point scheme in 3d that yield substantially less dispersionerror than their standard (unshifted) version. We illustrate this also with numerical experiments.
العلاقة: hal-03837707; https://hal.science/hal-03837707Test; https://hal.science/hal-03837707v2/documentTest; https://hal.science/hal-03837707v2/file/Shift_general_FD_scheme_MG-last-version-2.pdfTest
الإتاحة: https://doi.org/10.1137/22M1531142Test
https://hal.science/hal-03837707Test
https://hal.science/hal-03837707v2/documentTest
https://hal.science/hal-03837707v2/file/Shift_general_FD_scheme_MG-last-version-2.pdfTest -
3دورية أكاديمية
المؤلفون: Li, Yilun, Cottereau, Régis, Tie, Bing
المساهمون: Laboratoire de Mécanique Paris-Saclay (LMPS), CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Ecole Normale Supérieure Paris-Saclay (ENS Paris Saclay), Laboratoire de Mécanique et d'Acoustique Marseille (LMA ), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
المصدر: ISSN: 1742-6596 ; EISSN: 1742-6588.
مصطلحات موضوعية: Elastic wave propagation, imperfect periodic structures, dispersion relation and defect modes, [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph], [PHYS.PHYS.PHYS-COMP-PH]Physics [physics]/Physics [physics]/Computational Physics [physics.comp-ph]
الوصف: International audience ; Lack of periodicity in engineering structures can arise because of imperfections in the production process or a particular purpose to produce desirable physical effects. This contribution presents a series of numerical simulations that quantitatively characterize the influence of defects on the dispersion relation and associated eigenmodes of imperfect periodic structures. Local defects are introduced periodically on a scale larger than the size of the unit cell of the non-disturbed periodic structure. The observations reveal that these defects can give rise to non-propagating modes at frequencies situated within the bandgaps of the periodic structure. The eigenfrequency of such a defect mode varies monotonically with the amplitude of the defects, and its deformations are located in and around the disturbed cell. Furthermore, a bounded periodic medium with defects is studied by finite element analysis to demonstrate the existence of these defect modes in bounded imperfect periodic structures.
العلاقة: hal-04516732; https://hal.science/hal-04516732Test; https://hal.science/hal-04516732/documentTest; https://hal.science/hal-04516732/file/2024_JPCS_YLi.pdfTest
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4دورية أكاديمية
المؤلفون: Xu, Zongbo, Lognonné, Philippe
المساهمون: Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), ANR-19-CE31-0008,MAGIS,MArs Geophysical InSight(2019), ANR-21-CE01-0031,BRUIT-FM,Comprehension, prevention et utilisation du bruit sismologique en fond de mer(2021), ANR-18-IDEX-0001,Université de Paris,Université de Paris(2018)
المصدر: ISSN: 0956-540X.
مصطلحات موضوعية: Planetary seismology, Surface waves and free oscillations, Theoretical seismology, Wave propagation, Seismoacoustics, [SDU]Sciences of the Universe [physics]
الوصف: International audience ; Atmospheric and oceanic pressure perturbations deform the ground surface and the seafloor, respectively. This mechanical deformation, where the fluid perturbations propagate as plane waves, occurs not only on Earth but also on other planets/bodies with atmospheres, such as Mars, Titan and Venus. Studying this type of deformation improves our understanding of the mechanical interaction between the fluid layer (atmosphere/ocean) and the underlying solid planet/body, and aids investigation of subsurface structures. In this study, we utilize eigenfunction theory to unify existing theories for modelling this deformation and to comprehensively demonstrate possible scenarios of this deformation in homogeneous and 1-D elastic media, including static loading, air-coupled Rayleigh waves and leaky-mode surface waves. Our computations quantitatively reveal that the deformation amplitude generally decays with depth and that reducing seismic noise due to Martian atmosphere requires deploying seismometers at least 1 m beneath Martian surface. We also apply our theory to illustrate how this deformation and the corresponding air-to-solid energy conversion vary on different planetary bodies. Finally, we discuss how medium anelasticity and other factors affect this deformation.
العلاقة: hal-04398870; https://hal.science/hal-04398870Test; https://hal.science/hal-04398870/documentTest; https://hal.science/hal-04398870/file/Xu2023_Compliance.pdfTest
الإتاحة: https://doi.org/10.1093/gji/ggae005Test
https://hal.science/hal-04398870Test
https://hal.science/hal-04398870/documentTest
https://hal.science/hal-04398870/file/Xu2023_Compliance.pdfTest -
5دورية أكاديمية
المؤلفون: Morvaridi, M., Bosia, F., Brun, M., Dal Poggetto, V.F., Gliozzi, A.S., Miniaci, M., Croenne, C., Pugno, N.M., Carta, G.
المساهمون: Department of Applied Science and Technology Politecnico di Torino (DISAT), Politecnico di Torino = Polytechnic of Turin (Polito), University of Cagliari, Università degli Studi di Trento = University of Trento (UNITN), Acoustique - IEMN (ACOUSTIQUE - IEMN), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), JUNIA (JUNIA), Université catholique de Lille (UCL), supported by the European Commission H2020 FET Open “Boheme” grant no. 863179. G.C. and M.B.’s work has been performed under the auspices of GNFM-INDAM., European Project: 863179,H2020,H2020-FETOPEN-2018-2019-2020-01,BOHEME(2020)
المصدر: ISSN: 2331-7019 ; Physical Review Applied ; https://hal.science/hal-04526207Test ; Physical Review Applied, 2024, 21 (3), pp.034024. ⟨10.1103/PhysRevApplied.21.034024⟩.
مصطلحات موضوعية: valley Chern number, Elastic wave propagation, Topological protection, Metamaterials, Auxetic materials, Geometrical nonlinearity, Finite Element Method, Dynamic tunability, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]
الوصف: International audience ; In this paper, we discuss the possibility of achieving tunable topologically protected edge modes through the application of uniaxial prestrain in an auxetic metamaterial. The proposed structure consists of a thin slab with oriented cuts in a hexagonal lattice, where topologically protected band gaps are opened by introducing a controlled variation in selected cut lengths. Numerical simulations demonstrate the existence of topologically protected and scatter-free wave propagation in the structure at the interface between two subdomains with modified cells, in distinct frequency ranges. For the metamaterial considered in this study, this happens only in the presence of auxeticity. In addition, exploiting geometrical nonlinearity, the application of a uniaxial prestrain can be used to close the band gaps or to modify their frequency range, i.e., to weaken the localization effects or to shift the frequency at which they occur. The spatial and temporal variation of the applied strain field can thus be used for the dynamic tuning of metamaterial topological waveguiding properties, with applications in mechanical devices for logic operations and computation.
العلاقة: info:eu-repo/semantics/altIdentifier/arxiv/2306.06953; info:eu-repo/grantAgreement//863179/EU/Bio-Inspired Hierarchical MetaMaterials/BOHEME; hal-04526207; https://hal.science/hal-04526207Test; https://hal.science/hal-04526207/documentTest; https://hal.science/hal-04526207/file/Morvaridi_PhysRevApplied.21.034024.pdfTest; ARXIV: 2306.06953
الإتاحة: https://doi.org/10.1103/PhysRevApplied.21.034024Test
https://hal.science/hal-04526207Test
https://hal.science/hal-04526207/documentTest
https://hal.science/hal-04526207/file/Morvaridi_PhysRevApplied.21.034024.pdfTest -
6تقرير
المؤلفون: Pernet, Sébastien, Rivet, Matthias, Tordeux, Sébastien
المساهمون: DTIS, ONERA, Université de Toulouse Toulouse, ONERA-PRES Université de Toulouse, Modélisation et simulation de la propagation des ondes fondées sur des mesures expérimentales pour caractériser des milieux géophysiques et héliophysiques et concevoir des objets complexes (MAKUTU), Laboratoire de Mathématiques et de leurs Applications Pau (LMAP), Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS)-Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut Polytechnique de Bordeaux (Bordeaux INP), Bourse AMX pour la thèse de Matthias Rivet, Inria Bordeaux - Sud-Ouest
المصدر: https://inria.hal.science/hal-04504052Test ; RR-9544, Inria Bordeaux - Sud-Ouest. 2024.
مصطلحات موضوعية: Unique continuation, Hyperbolic formulation, Wave propagation, Transport equations, Acoustics, Elasticity, Maxwell's equations, Maxwell's equations Prolongement unique, formulation hyperbolique, propagation des ondes, équations de transport, acoustique, élasticité, équations de Maxwell, Prolongement unique, Equations de transport, Elasticité, Equations de Maxwell, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP]
الوصف: This document presents a simple proof of the unique continuation theorem for symmetric harmonic hyperbolic problems with constant coefficients. It only requires basic knowledge in functional analysis. ; Ce document propose une preuve simple du théorème de prolongement unique pour les problèmes hyperboliques harmoniques symétriques à coefficients constants. Celle-ci ne nécessite que des connaissances élémentaires en analyse fonctionnelle.
العلاقة: Report N°: RR-9544; hal-04504052; https://inria.hal.science/hal-04504052Test; https://inria.hal.science/hal-04504052/documentTest; https://inria.hal.science/hal-04504052/file/RR-9544%2FRR_9544.pdfTest
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7تقرير
المؤلفون: Chaumont-Frelet, Théophile
المساهمون: Reliable numerical approximations of dissipative systems (RAPSODI ), Laboratoire Paul Painlevé - UMR 8524 (LPP), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Inria Lille - Nord Europe, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Université de Lille-Centre National de la Recherche Scientifique (CNRS)
المصدر: https://inria.hal.science/hal-04478624Test ; 2024.
مصطلحات موضوعية: a posteriori error estimates, Maxwell's equations, time-harmonic wave propagation, finite element methods, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA], [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP]
الوصف: We propose a novel a posteriori error estimator for the Nédélec finite element discretization of time-harmonic Maxwell's equations. After the approximation of the electric field is computed, we propose a fully localized algorithm to reconstruct approximations to the electric displacement and the magnetic field, with such approximations respectively fulfilling suitable divergence and curl constraints. These reconstructed fields are in turn used to construct an a posteriori error estimator which is shown to be reliable and efficient. Specifically, the estimator controls the error from above up to a constant that tends to one as the mesh is refined and/or the polynomial degree is increased, and from below up to constant independent of p. Both bounds are also fully-robust in the low-frequency regime. The properties of the proposed estimator are illustrated on a set of numerical examples.
العلاقة: hal-04478624; https://inria.hal.science/hal-04478624Test; https://inria.hal.science/hal-04478624/documentTest; https://inria.hal.science/hal-04478624/file/chaumontfrelet_2024a.pdfTest
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8دورية أكاديمية
المؤلفون: Gonçalves, Bruno, Varela, Paulo, Silva, Antóni, da Silva, Filipe, Santos, Jorge, Ricardo, Emanuel, Vale, Alberto, Luís, Raúl, Nietiadi, Yohanes, Malaquias, Art, Belo, Jorge, Diaz, José, Ferreira, Jorge, Franke, Thomas, Biel, Wolfga, Heuraux, Stéphane, Ribeiro, Tiago, de Masi, Gianluca, Tudisco, Onofrio, Cavazzana, Roberto, Marchiori, Giuseppe, Arcangelo, Ocleto, D
المساهمون: Institut Jean Lamour (IJL), Institut de Chimie - CNRS Chimie (INC-CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)
المصدر: ISSN: 1424-8220 ; Sensors ; https://hal.univ-lorraine.fr/hal-04066332Test ; Sensors, 2023, 23, pp.3926. ⟨10.3390/s23083926⟩.
مصطلحات موضوعية: microwave antennas microwave propagation millimetre wave propagation microwave circuitry millimetre wave circuitry microwave measurements plasma diagnostic fusion plasma, microwave antennas, microwave propagation, millimetre wave propagation, microwave circuitry, millimetre wave circuitry, microwave measurements, plasma diagnostic, fusion plasma, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph]
الوصف: International audience ; Providing energy from fusion and finding ways to scale up the fusion process to commercial proportions in an efficient, economical, and environmentally benign way is one of the grand challenges for engineering. Controlling the burning plasma in real-time is one of the critical issues that need to be addressed. Plasma Position Reflectometry (PPR) is expected to have an important role in next-generation fusion machines, such as DEMO, as a diagnostic to monitor the position and shape of the plasma continuously, complementing magnetic diagnostics. The reflectometry diagnostic uses radar science methods in the microwave and millimetre wave frequency ranges and is envisaged to measure the radial edge density profile at several poloidal angles providing data for the feedback control of the plasma position and shape. While significant steps have already been given to accomplish that goal, with proof of concept tested first in ASDEX-Upgrade and afterward in COMPASS, important, groundbreaking work is still ongoing. The Divertor Test Tokamak (DTT) facility presents itself as the appropriate future fusion device to implement, develop, and test a PPR system, thus contributing to building a knowledge database in plasma position reflectometry required for its application in DEMO. At DEMO, the PPR diagnostic's in-vessel antennas and waveguides, as well as the magnetic diagnostics, may be exposed to neutron irradiation fluences 5 to 50 times greater than those experienced by ITER. In the event of failure of either the magnetic or microwave diagnostics, the equilibrium control of the DEMO plasma may be jeopardized. It is, therefore, imperative to ensure that these systems are designed in such a way that they can be replaced if necessary. To perform reflectometry measurements at the 16 envisaged poloidal locations in DEMO, plasma-facing antennas and waveguides are needed to route the microwaves between the plasma through the DEMO upper ports (UPs) to the diagnostic hall. The main integration approach for ...
العلاقة: hal-04066332; https://hal.univ-lorraine.fr/hal-04066332Test; https://hal.univ-lorraine.fr/hal-04066332/documentTest; https://hal.univ-lorraine.fr/hal-04066332/file/sensors-23-03926.pdfTest
الإتاحة: https://doi.org/10.3390/s23083926Test
https://hal.univ-lorraine.fr/hal-04066332Test
https://hal.univ-lorraine.fr/hal-04066332/documentTest
https://hal.univ-lorraine.fr/hal-04066332/file/sensors-23-03926.pdfTest -
9دورية أكاديمية
المؤلفون: Xie, Zhinan, Zheng, Yonglu, Cristini, Paul, Zhang, Xubin
المساهمون: Institute of Engineering Mechanics - China Earthquake Administration, Chinese Academy of Sciences Beijing (CAS), Laboratoire de Mécanique et d'Acoustique Marseille (LMA ), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)
المصدر: ISSN: 1671-3664 ; Earthquake Engineering and Engineering Vibration ; https://hal.science/hal-04292750Test ; Earthquake Engineering and Engineering Vibration, 2023, 22 (2), pp.407-421. ⟨10.1007/s11803-023-2170-3⟩.
مصطلحات موضوعية: Earthquake Engineering and Engineering Vibration Computational seismology Seismic anisotropy Wave propagation Elastodynamics Specialty Area: Observation and analysis of ground motions < Engineering Seismology Seismic hazard analysis and zonation < Engineering Seismology, Earthquake Engineering and Engineering Vibration Computational seismology, Seismic anisotropy, Wave propagation, Elastodynamics Specialty Area: Observation and analysis of ground motions < Engineering Seismology, Seismic hazard analysis and zonation < Engineering Seismology, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP]
الوصف: International audience
العلاقة: hal-04292750; https://hal.science/hal-04292750Test; https://hal.science/hal-04292750/documentTest; https://hal.science/hal-04292750/file/Earthquake_Engineering_Zhinan_2023.pdfTest
الإتاحة: https://doi.org/10.1007/s11803-023-2170-3Test
https://hal.science/hal-04292750Test
https://hal.science/hal-04292750/documentTest
https://hal.science/hal-04292750/file/Earthquake_Engineering_Zhinan_2023.pdfTest -
10مؤتمر
المؤلفون: Faucher, Florian
المساهمون: Modélisation et simulation de la propagation des ondes fondées sur des mesures expérimentales pour caractériser des milieux géophysiques et héliophysiques et concevoir des objets complexes (MAKUTU), Laboratoire de Mathématiques et de leurs Applications Pau (LMAP), Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS)-Université de Pau et des Pays de l'Adour (UPPA)-Centre National de la Recherche Scientifique (CNRS)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut Polytechnique de Bordeaux (Bordeaux INP)
المصدر: Workshop RNTW04 - Synergistic workshop on Rich and Nonlinear tomography ; https://hal.science/hal-04355871Test ; Workshop RNTW04 - Synergistic workshop on Rich and Nonlinear tomography, Jun 2023, Cambridge, United Kingdom ; https://www.newton.ac.uk/event/rntw04Test/
مصطلحات موضوعية: Inverse Problem, Seismic imaging, Numerical methods, Wave propagation, [MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP]
جغرافية الموضوع: Cambridge, United Kingdom
الوصف: International audience ; We consider the propagation of waves in media with attenuation. Attenuation is a frequency-dependent phenomenon and several constitutive laws exist to consider it, each leading to different models of wave equations. In the inverse problem for the reconstruction of the physical properties from the measurements of waves, considering a medium with attenuation leads to additional unknown coefficients to recover (those that represent the attenuation), while the precise attenuation law characterizing the medium is also unknown a priori. In this work, we consider the inverse wave problem for visco-acoustic and visco-elastic media. We use time-harmonic formulations which allow us to unify the models of attenuation using complex-valued parameters and illustrate the wave propagation depending on the attenuation model. We carry out quantitative reconstruction with attenuation model uncertainty using an iterative minimization procedure. Furthermore, we also consider the case of reflecting boundaries surrounding the sample, which lead to multiple reflections within the domain and complicate the reconstruction.
العلاقة: hal-04355871; https://hal.science/hal-04355871Test; https://hal.science/hal-04355871/documentTest; https://hal.science/hal-04355871/file/abstract_INI.pdfTest
