ESPCI web site
Le séminaire hebdomadaire du laboratoire PMMH a lieu tous les vendredis à 11h, au premier étage Barre Cassan, campus Jussieu (plan).
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France
Tel : (33) 1 40 79 45 22
Séminaire PMMH - Ory Schnitzer ( Imperial College London)
Asymptotic models of wave propagation and resonance in micro-structured media
The study of microstructured media in acoustic settings is undergoing a considerable revival, with ideas originating from electromagnetism, photonic crystals and metamaterials influencing structured acoustic devices. Fundamentally, these advancements rely on incorporating resonances to effectively control wave propagation, localisation and attenuation. In this talk I will discuss several elementary acoustic examples, using the language of scalings and singular perturbations, where the dynamics on small length scales (compared to the wavelength) have an appreciable effect on propagation. I'll first revisit the classical problem of extraordinary transmission through narrow slits. I'll show that straining the frequency about the slit resonances and accounting for end effects using matched asymptotics yields a simple approximate theory that agrees remarkably well with available experimental data. I'll next introduce a class of phononic crystals that behave like a network of directly coupled Helmholtz resonators ; such structured media exhibit nonlinear dispersion in a wide subwavelength regime (in contrast to the narrow bandwidth of traditional subwavelength metamaterials formed of weakly coupled resonators). I will consider both 2D realisations, using densely packed phononic crystals, and 3D realisations, using “phononic box crystals,” namely arrays of joined perforated boxes. I'll show that such media are asymptotically governed by discrete wave equations and demonstrate their use for controlling band gaps, dynamic anisotropy, Dirac points, trapped modes, emission and slow propagation. Lastly, I'll describe surprising predictions regarding the acoustic properties of superhydrophobic surfaces, whose special properties are usually considered in the context of wetting and drag reduction.
Séminaires (4)
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Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…)
Instructions générales pour les conférenciers
Le public du séminaire est très hétérogène (rien qu’au PMMH nous travaillons sur des thématiques très diverses, mécanique des fluides, des milieux granulaires, des solides, physique statistique, physique du mouillage, micro-fluidique, biophysique,...) l’objectif est donc de ne pas faire un séminaire trop spécialiste : au moins la première moitié du séminaire à un niveau accessible pour celui qui ne connaît rien sur le sujet.
Le séminaire a lieu à 11h. rendez-vous 15 minutes avant pour installer et tester la projection.
Le séminaire dure environ 45 minutes pour laisser un peu de temps pour discuter à la fin.
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- Séminaire de Mécanique des Fluides de l’Institut Jean le Rond d’Alembert
- Séminaires du laboratoire MSC, Paris VII
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