Publications de Outi Supponen | EPFL Graph Search

Gravity-Independent Oscillate Boiling

Heat transfer in nucleate boiling relies on the detachment and rise of the boiling bubble, in which gravity plays the dominant role. Previous studies showed that in the absence of gravity, the bubble fails to rise, causing the dryout of the heater and sign ...

SPRINGER2019

High-speed imaging of high pressures produced by cavitation bubbles

Mohamed Farhat, Danail Obreschkow, Outi Supponen

Cavitation bubbles, when correctly tuned, may provide interesting mechanical and chemical effects to their surroundings owing to their violent collapse. Such an event may produce high-speed liquid jetting, extreme heating, as well as pressures of thousands ...

SPIE-INT SOC OPTICAL ENGINEERING2019

Detailed experiments on weakly deformed cavitation bubbles

Mohamed Farhat, Danail Obreschkow, Nicolas Dorsaz, 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

Jetting from cavitation bubbles due to multiple shockwaves

Mohamed Farhat, Outi Supponen

We present experimental observations of microjets formed by cavitation microbubbles. An underwater electric discharge, applied beneath a flat free surface, produces a primary compression wave, which undergoes several phase inversions upon reflections from ...

AMER INST PHYSICS2018

Rebounds of deformed cavitation bubbles

Mohamed Farhat, Danail Obreschkow, Outi Supponen

Presented here are experiments clarifying how the deformation of cavitation bubbles affects their rebound. Rebound bubbles carry the remaining energy of a bubble following its initial collapse, which dissipates energy mainly through shock waves, jets, and ...

AMER PHYSICAL SOC2018

Shock waves from nonspherical cavitation bubbles

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

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

Collapse phenomena of deformed cavitation bubbles

Outi Supponen

Cavitation bubbles are a topic of long-standing interest owing to the powerful phenomena associated with their collapse. Their unique ability to focus energy typically causes damage in hydraulic machinery (turbines, pumps, propellers, ...) but, if managed ...

EPFL2017

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

Numerical simulation of a collapsing bubble subject to gravity

Mohamed Farhat, Outi Supponen

The present paper focuses on the simulation of the expansion and aspherical collapse of a laser-generated bubble subjected to an acceleration field and comparison of the results with instances from high-speed videos. The interaction of the liquid and gas i ...

Amer Inst Physics2016

Simulation of bubble expansion and collapse in the vicinity of a free surface

Mohamed Farhat, Outi Supponen

The present paper focuses on the numerical simulation of the interaction of laser-generated bubbles with a free surface, including comparison of the results with instances from high-speed videos of the experiment. The Volume Of Fluid method was employed fo ...

Amer Inst Physics2016

Scaling laws for jets of single cavitation bubbles

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

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

The inner world of a collapsing bubble

Mohamed Farhat, Danail Obreschkow, Philipp Kobel, Outi Supponen

Amer Inst Physics2015