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Concept

Self-oscillation

Publications associées (26)

Experimental observation of topological transition in linear and nonlinear parametric oscillators

Romain Christophe Rémy Fleury, Benjamin Apffel

Parametric oscillators are examples of externally driven systems that can exhibit two stable states with opposite phase depending on the initial conditions. In this work, we propose to study what happens when the external forcing is perturbed by a continuo ...

2024

Self-sustained dynamics and forced resonant oscillations in flows: cross-junction jets and sloshing liquids

Alessandro Bongarzone

In engineering, oscillatory instabilities and resonances are often considered undesirable flow features and measures are taken to avoid them. This may include avoiding certain parametric regions or implementing control and mitigation strategies. However, t ...

EPFL2023

Anisotropic and nonlinear transport in microstructured 3D topological semimetals

Xiangwei Huang

Topological semimetals are frequently discussed as materials platforms for future electronics that exploit the remarkable properties of their quasiparticles. These ideas are mostly based on dispersion relations that mimic relativistic particles, such as We ...

EPFL2022

Learning dynamical systems with bifurcations

Aude Billard, Farshad Khadivar, Ilaria Lauzana

Trajectory planning through dynamical systems (DS) provides robust control for robots and has found numerous applications from locomotion to manipulation. However, to date, DS for controlling rhythmic patterns are distinct from DS used to control point to ...

Elsevier2021

Impinging planar jets: hysteretic behaviour and origin of the self-sustained oscillations

Philippe Renaud, François Gallaire, Arnaud Bertsch, Alessandro Bongarzone

The experimental and numerical investigation presented by Bertsch et al. (Phys. Rev. Fluids, vol. 5, 2020a, p. 054202) describes the self-sustained oscillations induced by the interaction of two impinging jets in microfluidic devices. While the oscillatory ...

Cambridge University Press2021

Laser photo-detachment combined with Langmuir probe in magnetized electronegative plasma: how the probe size affects the plasma dynamic?

Ivo Furno, Riccardo Agnello

Laser photo-detachment combined with a Langmuir probe (LP) is used to diagnose negative ion properties in electronegative plasmas. The technique relies on the combined use of a laser pulse and an LP. The laser pulse converts negative ions into electron-ato ...

2021

Controlling oscillations in high-order Discontinuous Galerkin schemes using artificial viscosity tuned by neural networks

Jan Sickmann Hesthaven, Deep Ray, Niccolo' Discacciati

High-order numerical solvers for conservation laws suffer from Gibbs phenomenon close to discontinuities, leading to spurious oscillations and a detrimental effect on the solution accuracy. A possible strategy to reduce it comprises adding a suitable amoun ...

ACADEMIC PRESS INC ELSEVIER SCIENCE2020

VO2 oscillators coupling for Neuromorphic Computation

Mihai Adrian Ionescu, Igor Stolichnov, Kirsten Emilie Moselund, Elisabetta Corti

New computation schemes inspired by biological processes can outperform standard von-Neumann architectures in dealing with complex and unstructured tasks. As a new approach, systems of frequency-locked, coupled oscillators are investigated using the phase ...

IEEE2019

Optimal Control of Part Load Vortex Rope in Francis Turbines

François Avellan, François Gallaire, Simon Pasche

The mitigation of the precessing vortex core developing in the draft tube of Francis turbines operating under part load conditions is crucial to increase the operation flexibility of these hydraulic machines to balance the massive power production of inter ...

ASME2019

An Event-Driven Closed-Loop System for Real-Time FES Control

Silvestro Micera, Danilo Demarchi, Andrea Crema

Active functional rehabilitation procedures, exoskeleton application and prosthesis employment are essential tools for the society life reinstatement of subjects affected by neuromuscular disorders or victims of serious physical accident. In this paper we ...

IEEE2019

Physics of Dissipative Kerr Solitons in Optical Microresonators and Application to Frequency Synthesis

Erwan Guillaume Albert Lucas

Optical-frequency combs, that is spectra of equidistant coherent optical lines, have revolutionized the precision measurements of time and frequency. In 2007 a new method to generate optical frequency combs was discovered. In contrast to conventional gener ...

EPFL2019

Autonomous illumination control for localization microscopy

Suliana Manley, Kyle Michael Douglass

Super-resolution fluorescence microscopy improves spatial resolution, but this comes at a loss of image throughput and presents unique challenges in identifying optimal acquisition parameters. Microscope automation routines can offset these drawbacks, but ...

OPTICAL SOC AMER2018

Dynamics and Optimal Control of Self-Sustained Instabilities in Laminar and Turbulent Swirling Flows: Application to the Part Load Vortex Rope in Francis Turbines

Simon Pasche

In 2050, the European commission plans to achieve actual energetic transition, which contributes in meeting the climate change challenges by moving away from the fossil fuels and by developing a competitive low-carbon economy. As a consequence, a foreseeab ...

EPFL2018

Axisymmetric oscillations at L-H transitions in JET: M-mode

Nicola Vianello, Antonio José Pereira de Figueiredo

L to H transition studies at JET have revealed an n = 0, m = 1 magnetic oscillation starting immediately at the L to H transition (called M-mode for brevity). While the magnetic oscillation is present a weak ELM-less H-mode regime is obtained, with a clear ...

IOP Publishing Ltd2017

Nanoscale structural oscillations in perovskite oxides induced by oxygen evolution

Vasiliki Tileli

Understanding the interaction between water and oxides is critical for many technological applications, including energy storage, surface wetting/self-cleaning, photocatalysis and sensors. Here, we report observations of strong structural oscillations of B ...

Nature Publishing Group2017

The viscous torsional pendulum

François Gallaire, Francesco Viola

A disk that is free to rotate about its axis and connected to a torsional spring behaves as a damped oscillator when twisted and released. The initial elastic energy is periodically turned to kinetic energy and it gets progressively dissipated by the visco ...

Academic Press Ltd- Elsevier Science Ltd2017

MEMS cantilever sensor array oscillators: Theory and experiments

Yusuf Leblebici, Ulas Adiyan

This paper demonstrates that an array of cantilever sensors can be operated simultaneously at resonance using a single actuator and a single photodetector. Self-sustained oscillations (SSOs) of cantilevers can be achieved in a feed-back loop using gain sat ...

Elsevier2016

Persistence, period and precision of autonomous cellular oscillators from the zebrafish segmentation clock

Andrew Charles Oates

In vertebrate development, the sequential and rhythmic segmentation of the body axis is regulated by a "segmentation clock". This clock is comprised of a population of coordinated oscillating cells that together produce rhythmic gene expression patterns in ...

2016

Resonance in swirling wakes and sloshing waves : non-normal and sublinear effects

Francesco Viola

Similarly to mechanical structures, stable flows can exhibit resonance when perturbed by an impulsive or harmonic forcing. Swirling wakes and sloshing waves belong to this kind of flows and manifest large energy response when excited close to their natural ...

EPFL2016

Too big to grow : self-consistent model for nonlinear saturation in open shear flows

Vladislav Mantic Lugo

Open flows, such as wakes, jets, separation bubbles, mixing layers, boundary layers, etc., develop in domains where fluid particles are continuously advected downstream. They are encountered in a wide variety of situations, ranging from nature to technolog ...

EPFL2015