Publications associées à Théorie de bifurcation et de stabilité pour une équation de Schrödinger avec une non-linéarité compacte

From thin plates to Ahmed bodies: linear and weakly nonlinear stability of rectangular prisms

Edouard Boujo, Giuseppe Antonio Zampogna

We study the stability of laminar wakes past three-dimensional rectangular prisms. The width-to-height ratio is set to W/H = 1.2, while the length-to-height ratio 1/6 < L/H < 3 covers a wide range of geometries from thin plates to elongated Ahmed bodies. F ...

Cambridge University Press2023

The effects of Prandtl number on the nonlinear dynamics of Kelvin-Helmholtz instability in two dimensions

Jeremy Peter Parker

It is known that the pitchfork bifurcation of Kelvin-Helmholtz instability occurring at minimum gradient Richardson number Ri(m) similar or equal to 1/4 in viscous stratified shear flows can be subcritical or supercritical depending on the value of the Pra ...

Cambridge University Press2021

Stability of standing waves for a nonlinear Klein-Gordon equation with delta potentials

François Samer Genoud

In this paper, we study local well-posedness and orbital stability of standing waves for a singularly perturbed one-dimensional nonlinear Klein-Gordon equation. We first establish local well-posedness of the Cauchy problem by a fixed point argument. Unlike ...

2019

Turbulent patterns in wall-bounded shear flows: invariant solutions and their bifurcations

Florian Reetz

When laminar shear flows in large wall-bounded domains transition to turbulence, the flow exhibits spatio-temporally chaotic dynamics. Despite its chaotic dynamics, the flow may self-organize into characteristic spatially periodic patterns of unknown origi ...

EPFL2019

Accurate Profile Measurement of the low Intensity Secondary Beams in the CERN Experimental Areas

Inaki Ortega Ruiz

The CERN accelerators deliver a wide spectrum of secondary beams to the Experimental Areas. These beams are composed of hadrons, leptons, and heavy ions that can vary greatly in momentum (1 GeV/c to 400 GeV/c) and intensity (10^2 to 10^8 particles per seco ...

EPFL2018

Dynamical Behavior and Stability Analysis of Hydromechanical Gates

Paolo Perona, Fabian Alexander Bernhard

This study revisits the stability of hydromechanical gates for upstream water surface regulation, also known as AMIL gates. AMIL gates are used in irrigation canals, where they are often installed in series. From the regulation perspective, instabilities a ...

American Society of Civil Engineers2017

Decomposition Strategies for Nonconvex Problems, a Parametric Approach

Jean-Hubert Hours

This thesis deals with the development of numerical methods for solving nonconvex optimisation problems by means of decomposition and continuation techniques. We first introduce a novel decomposition algorithm based on alternating gradient projections and ...

EPFL2016

Approximate cloaking for the full wave equation via change of variables: The Drude-Lorentz model

Hoài-Minh Nguyên

This paper concerns approximate cloaking by mapping for a full, but scalar wave equation, when one allows for physically relevant frequency dependence of the material properties of the cloak. The paper is a natural continuation of [20], but here we employ ...

Elsevier2016

Emissions scenarios without measures 1990-2030

Philippe Thalmann, Bettina Schäppi, Marc Vielle

The goal of this study is to estimate the net impact of all measures implemented in the context of the Swiss energy and climate policies on CO2 emissions from combustion processes between 1990 and 2030. The study provides a projection of CO2 emissions unti ...

INFRAS EPFL2016

Modelling of Mechanical Interaction in Piezoelectric Actuated Resonant System

Dan Shi

Automatic assembly system has been continuously drawing attention since the beginning of the 20th century. Parts feeding system is one of the important subsystems. The parts feeding system is used for delivering bulk parts into separated individual parts. ...

EPFL2016

A vector field method on the distorted Fourier side and decay for wave equations with potentials

Joachim Krieger, Roland Donninger

We study the Cauchy problem for the one-dimensional wave equation

\partial_t^2 u(t,x)-\partial_x^2 u(t,x)+V(x)u(t,x)=0.

The potential

V

is assumed to be smooth with asymptotic behavior

V(x)\sim -\tfrac14 |x|^{-2}\mbox{ as } |x|\to \infty.

...

2016

Damage pattern and damage progression on breakwater roundheads under multidirectional waves

Francesco Comola, Lorenzo Martinelli

An experimental model test study is carried out to investigate damage pattern and progression on a rock armoured breakwater roundhead subjected to multidirectional waves. Concerning damage pattern, the most critical sector is observed to shift leeward with ...

Elsevier2014

Odd linking and bifurcation in gaps: the weakly indefinite case

In this paper, we consider nonlinear Schrodinger equations of the following type: -Delta u(x) + V (x) u(x) -q(x)|u(x)|sigma u(x) =lambda u(x), x is an element of R-N, u is an element of H-1(R-N) \ {0}, where N >= 2 and sigma > 0. We concentrate on situatio ...

Royal Society of Edinburgh Scotland Foundation, Cambridge2013

On the stability of travelling waves with vorticity obtained by minimization

Boris Buffoni

We modify the approach of Burton and Toland Comm. Pure Appl. Math. LXIV. 975-1007 (2011) to show the existence of periodic surface water waves with vorticity in order that it becomes suited to a stability analysis. This is achieved by enlarging the functio ...

Springer Basel2013

Modelling and Optimal Design of a Ring-type Structure for the Generation of a Traveling Wave

Yves Perriard, Yoan René Cyrille Civet, Dan Shi

Traveling wave generation in a ring type stator has been studied. The basic working principle to create traveling wave has been modelled by the superposition of two orthogonal standing waves. Theoretical analysis shows that the length to radius ratio affec ...

2013

Numerical Simulation of the Rock SHPB Test with a Special Shape Striker Based on the Discrete Element Method

Yang Zou, Xing Li

A split Hopkinson pressure bar system with a special shape striker has been suggested as the test method by the International Society for Rock Mechanics (ISRM) to determine the dynamic characteristics of rock materials. In order to further verify this test ...

Springer Verlag2013

Dynamical Movement Primitives: Learning Attractor Models for Motor Behaviors

Auke Ijspeert

Nonlinear dynamical systems have been used in many disciplines to model complex behaviors, including biological motor control, robotics, perception, economics, traffic prediction, and neuroscience. While often the unexpected emergent behavior of nonlinear ...

Massachusetts Institute of Technology Press2013

Effect Of Distinct Conductive And Thermodynamic Temperatures On The Reflection Of Plane Waves In Micropolar Elastic Half-Space

Kunal Sharma

The present investigation is concerned with wave propagation in micropolar thermoelastic solid half space with distinct conductive and thermodynamic temperatures. Reflection of plane waves incident obliquely at the free surface of micropolar generalized th ...

Univ Politehnica Bucharest, Sci Bull2013

Bifurcation Analysis at a Singular Soliton State in Fiber Couplers

Boris Buffoni

The system {-u '' + u = u(3) + lambda v, u(x)= u(-x) is an element of R, x is an element of R, -v '' + v = v(3) + lambda u, v(x) = v(-x) is an element of R, x is an element of R, describes pulses in nonlinear fiber couplers. It has the family (U1+lambda, - ...

Advanced Nonlinear Studies, Inc2012

Study on room modal equalization at low frequencies with electroacoustic absorbers

Hervé Lissek, Romain Boulandet, Iris Rigas, Etienne Thierry Jean-Luc Rivet

Nowadays, requirements for acoustic treatments in rooms are ever more demanding in terms of performance and compactness. A recurring issue in closed spaces is the occurrence of standing waves and acoustic interferences at low frequencies. These unwanted ph ...

2012