Concept

Bang supersonique

Publications associées (33)

A Review of Modeling, Design and Performance Assessment of Linear Electromagnetic Motors for High-Speed Transportation Systems

Mario Paolone, André Hodder, Lucien André Félicien Pierrejean, Simone Rametti

Linear electromagnetic motors (LEMs) have been proposed, developed and used to propel high-speed (i.e. speed > 100 m/s) levitating vehicles. However, few real implementations have demonstrated the feasibility of these machines at such speeds. Furthermore, ...

2024

Femtosecond laser-shockwave induced densification in fused silica

Yves Bellouard, Pieter Vlugter, Arunkrishnan Radhakrishnan, Julien Gilles Edgar Gateau

A tightly focused femtosecond laser-beam in the non-ablative regime can induce a shockwave sufficiently intense to reach local pressures in the giga-Pascal range or more. In a single beam configuration, the location of the highest-pressure zone is nested w ...

2022

Effect of femtosecond laser-induced high pressure on fused silica polymorphism

Arunkrishnan Radhakrishnan

High-pressure studies in silica are of great interest to earth and planetary sciences. Highpressure phases are rarely found in nature as a result of shock events like meteorite impacts orvolcanic events in nature. Recreating these phases remains a challeng ...

EPFL2022

Experimental investigation of surface roughness effect on a free-flight sphere in a Ludwieg tube

Seong-Hyeon Park

Understanding the aerodynamic coefficients of meteoroid fragments, deorbiting space debris, or launch vehicle stages through atmospheric reentry is essential for ground risk assessments. In high enthalpy flow, surface roughness is a crucial factor affectin ...

KOREAN SOC MECHANICAL ENGINEERS2022

Crack propagation speeds in weak snowpack layers

Johan Alexandre Philippe Gaume, Jürg Schweizer, Bertil Trottet, Grégoire Bobillier, Alec van Herwijnen

For the release of a slab avalanche, crack propagation within a weak snowpack layer below a cohesive snow slab is required. As crack speed measurements can give insight into underlying processes, we analysed three crack propagation events that occurred in ...

CAMBRIDGE UNIV PRESS2021

Crack front waves: A 3D dynamic response to a local perturbation of tensile and shear cracks

Jean-François Molinari, Fabian Barras, Damien Spielmann, Fatima-Ezzahra Fekak

Crack front waves are long-lived perturbations propagating along the crack front. They are triggered by heterogeneities on the crack plane, as for instance tough asperities, which disturb the crack front shape. Crack front waves are thought to leave a trac ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Design and development of the efficient anguilliform swimming robot- MAR

Auke Ijspeert, Peter Eckert, Anouk Looijestijn

Propulsion of swimming robots at the surface and underwater is largely dominated by rotary propellers due to high thrust, but at the cost of low efficiency. Due to their inherently high speed turning motion, sharp propeller blades and generated noise, they ...

IOP PUBLISHING LTD2020

Measurements of ion velocity and wave propagation in a hollow cathode plume

The mechanism responsible for the production of energetic ions in the plume of hollow cathodes for electric propulsion is still an open issue. These ions are of concern to cathode and thruster lifetime, particularly for cathodes operating at high (>20 A) d ...

IOP PUBLISHING LTD2019

Two-fluid plasma model for radial Langmuir probes as a converging nozzle with sonic choked flow, and sonic passage to supersonic flow

Ivo Furno, Alan Howling, Philippe Frédérique Bruno Guittienne

Using the Lambert function, Guittienne et al. [Phys. Plasmas 25, 093519 (2018)] derived two-fluid solutions for radial Langmuir probes in collisionless and isothermal plasma. In this Brief Communication, we point out the close analogy with classical compre ...

2019

Interplay between Process Zone and Material Heterogeneities for Dynamic Cracks

Thibault Didier Roch

In the context of dynamic fracture propagation along an heterogeneous domain, it has been shown in [1] how the presence of small-scale heterogeneities can impact the rupture dynamics of a crack. In the particular case of a mode-II crack propagating along a ...

2019

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