Publications de Philipp Kobel | EPFL Graph Search

Detailed experiments on weakly deformed cavitation bubbles

Mohamed Farhat, Nicolas Dorsaz, Danail Obreschkow, Philipp Kobel, Outi Supponen

We present high-precision experiments conducted with the aim to better characterise weak deformations of single cavitation bubbles. Using two needle hydrophones and a high-speed photodetector, we record the timings of shock waves and luminescence emitted a ...

SPRINGER2019

Shock waves from nonspherical cavitation bubbles

Mohamed Farhat, Outi Supponen, Nicolas Dorsaz, Danail Obreschkow, Philipp Kobel, Marc Tinguely

We present detailed observations of the shock waves emitted at the collapse of single cavitation bubbles using simultaneous time-resolved shadowgraphy and hydrophone pressure measurements. The geometry of the bubbles is systematically varied from spherical ...

Amer Physical Soc2017

Luminescence from cavitation bubbles deformed in uniform pressure gradients

Mohamed Farhat, Danail Obreschkow, Philipp Kobel, Outi Supponen

Presented here are observations that demonstrate how the deformation of millimetric cavitation bubbles by a uniform pressure gradient quenches single-collapse luminescence. Our innovative measurement system captures a broad luminescence spectrum (wavelengt ...

2017

Scaling laws for jets of single cavitation bubbles

Mohamed Farhat, Nicolas Dorsaz, Danail Obreschkow, Philipp Kobel, Outi Supponen, Marc Tinguely

Fast liquid jets, called micro-jets, are produced within cavitation bubbles experiencing an aspherical collapse. Here we review micro-jets of different origins, scales and appearances, and propose a unified framework to describe their dynamics by using an ...

Cambridge University Press2016

Radial Shock Wave Devices Generate Cavitation

Mohamed Farhat, Philipp Kobel

Background Conflicting reports in the literature have raised the question whether radial extracorporeal shock wave therapy (rESWT) devices and vibrating massage devices have similar energy signatures and, hence, cause similar bioeffects in treated tissues. ...

Public Library of Science2015

The inner world of a collapsing bubble

Mohamed Farhat, Danail Obreschkow, Outi Supponen, Philipp Kobel

Amer Inst Physics2015

Inferring the magnetic field vector in the quiet Sun III. Disk variation of the Stokes profiles and isotropism of the magnetic field

Philipp Kobel

Recent investigations of the magnetic field vector properties in the solar internetwork have provided diverging results. While some works found that the internetwork is mostly pervaded by horizontal magnetic fields, other works argued in favor of an isotro ...

EDP Sciences2013

The quest for the most spherical bubble: experimental setup and data overview

Mohamed Farhat, Nicolas Dorsaz, Danail Obreschkow, Philipp Kobel, Marc Tinguely, Aurèle De Bosset

We describe a recently realized experiment producing the most spherical cavitation bubbles today. The bubbles grow inside a liquid from a point plasma generated by a nanosecond laser pulse. Unlike in previous studies, the laser is focussed by a parabolic m ...

Springer Verlag2013

MicroFactory : Miniaturized Modular Cleanroom Concept for Automated Production

Philipp Kobel

Production in a controlled environment is becoming an increasingly important issue in various branches of industry. In the food, pharmaceutical, optical and semiconductor industries, today’s mass production would not be possible without so-called “cleanroo ...

EPFL2013

The continuum intensity as a function of magnetic field II. Local magnetic flux and convective flows

Philipp Kobel

Context. To deepen our understanding of the role of small-scale magnetic fields in active regions (ARs) and in the quiet Sun (QS) on the solar irradiance, it is fundamental to investigate the physical processes underlying their continuum brightness. Previo ...

2012