Recherche

Afficher tous les résultats pour

Accueil

Personne

Mohamed Farhat

Cette personne a quitté l’EPFL

À propos
Confidentialité
Mentions légales

Graph Chatbot

Publications associées (118)

Page 4 sur 6

An innovative method of pressure measurement inside a laser-induced cavitation bubble

Mohamed Farhat

This study proposes a novel method for measuring the pressure inside a laser-induced cavitation bubble during its expansion. Based on Paschen's theory, which relates electrical breakdown to gas pressure, applied voltage, and electrode distance, our approac ...

Aip Publishing2024

Hydrodynamic Damping Identification from an Impulse Response of a Vibrating Blade

François Avellan, Mohamed Farhat, Steven Roth, Cécile Münch-Alligné, Martin Calmon

In the present study, the identification of hydrodynamic damping is investigated in the case of 2D blade placed in the test section of the EPFL High Speed Cavitation Tunnel. A non intrusive technique, based on a spark generated bubble, is used to generate ...

Brno University of Technology2009

Detailed experiments on weakly deformed cavitation bubbles

Mohamed Farhat, Philipp Kobel, Danail Obreschkow, Nicolas Dorsaz, Philippe 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

Hydrodynamic mechanisms of aggressive collapse events in leading edge cavitation

Mohamed Farhat, Ali Amini

Transient cavities generated from unsteady leading-edge cavitation may undergo aggressive collapses which are responsible for cavitation erosion. In this paper, we studied the hydrodynamic mechanisms of these events in the leading edge cavitation formed ov ...

SPRINGER2020

Roll-up region of tip vortex: numerical investigation

Mohamed Farhat, Azin Amini, Matthieu Dreyer, Ali Amini, Martino Reclari

The appearance of gas-filled vortices at the tip of hydraulic machines blades is usually associated with increase of losses, vibrations, noise and erosion risk. The understanding of the roll-up region, where the boundary layer on the pressure side crosses ...

IOP Publishing2019

Cavitation Bubbles inside Spherical Water Drops in Microgravity

Mohamed Farhat

We studied spark-generated bubble inside stable water drops produced in microgravity. The closed and isolated liquid geometry results in a unique confinement of subsequent shockwaves, since the latter bounce of the free surface. This setting results in an ...

Warwick University, UK2008

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

LES investigation of the influence of cavitation on flow patterns in a confined tip-leakage flow

Mohamed Farhat

In the present paper, Large Eddy Simulations combined with the Zwart-Gerber-Belamri cavitation model are conducted to study the flow characteristics in a tip-leakage flow. A reasonable agreement is obtained between the numerical and experimental data. With ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Particle Imaging Velocimetry Evaluation of Intracranial Stents in Sidewall Aneurysm: Hemodynamic Transition Related to the Stent Design

Mohamed Farhat, Pierre Bouillot

We investigated the flow modifications induced by a large panel of commercial-off-the-shelf (COTS) intracranial stents in an idealized sidewall intracranial aneurysm (IA). Flow velocities in IA silicone model were assessed with and without stent implantati ...

Public Library of Science2014

Efficient and reproducible mammalian cell bioprocesses without probes and controllers?

Florian Maria Wurm, Mohamed Farhat, David Hacker, Lucia Baldi Unser, Matthieu Dreyer, Martino Reclari

Bioprocesses for recombinant protein production with mammalian cells are typically controlled for several physicochemical parameters including the pH and dissolved oxygen concentration (DO) of the culture medium. Here we studied whether these controls are ...

Elsevier2011

One-dimensional analysis of full load draft tube surge

François Avellan, Mohamed Farhat, Christophe Nicolet

A previous report by the present authors [1] clarified the diffuser effect of the draft tube and the effects of swirl in the runner downstream on the hydraulic instabilities in power generation plants. The present study was intended to study the effect of ...

International Association For Hydraulic Research2008

Geometrical deployment for braided stent

Mohamed Farhat, Pierre Bouillot

The prediction of flow diverter stent (FDS) implantation for the treatment of intracranial aneurysms (IAs) is being increasingly required for hemodynamic simulations and procedural planning. In this paper, a deployment model was developed based on geometri ...

Elsevier2016

RANS computations of a confined cavitating tip-leakage vortex

Mohamed Farhat, Matthieu Dreyer

Cavitating tip-leakage vortices appear in several hydrodynamic flows such as marine propellers or Kaplan turbines. Cavitating computations are a challenging topic since several keys issues are an ongoing work such as the definition of a universal mass sour ...

2018

Cavitation bubble behavior inside a liquid jet

François Avellan, Mohamed Farhat, Peter Monkewitz, Etienne Robert

The growth and collapse of laser-induced vapor cavities inside axisymmetric free-falling liquid water jets have been studied. Bubbles of different size are generated at various distances from the jet axis and the effects on the jet interface are recorded b ...

2007

Modal behavior of a reduced scale pump turbine impeller. Part II: Numerical simulation

François Avellan, Mohamed Farhat, Xiaopeng Huang

A numerical simulation has been carried out to analyze the modal behavior of a reduced scale pump-turbine impeller. The simulation has been done using FEM method, in air and in water. The same boundary conditions than in the experiment were considered: fre ...

International Association For Hydraulic Research2010

Influence of the Pump-Turbine Guide Vanes Vibrations on the Pressure Fluctuations in the Rotor-Stator Vaneless Gap

François Avellan, Mohamed Farhat, Vlad Hasmatuchi, Steven Roth

We investigate the Rotor-Stator Interaction in a pump-turbine reduced scale model by considering fluid-structure coupling. The pressure fluctuations amplitude in the rotor-stator vaneless gap has generally been shown to increase linearly with the operating ...

2011

Confined shocks inside isolated liquid volumes: A new path of erosion?

Mohamed Farhat, Philipp Kobel, Danail Obreschkow, Nicolas Dorsaz, Philippe Kobel, Marc Tinguely

The unique confinement of shock waves inside isolated liquid volumes amplifies the density of shock–liquid interactions. We investigate this universal principle through an interdisciplinary study of shock-induced cavitation inside liquid volumes, isolated ...

American Institute of Physics2011

Numerical and experimental investigation of shedding mechanisms from leading-edge cavitation

Mohamed Farhat, Ali Amini

Leading-edge cavitation is responsible of the generation of transient cavities, usually made of clouds of bubbles. These transient cavities travel downstream to high-pressure regions and collapse violently, leading to noise and vibration as well as erosion ...

PERGAMON-ELSEVIER SCIENCE LTD2019

Cavitation Bubble Dynamics inside Liquid Drops in Microgravity

Mohamed Farhat, Philipp Kobel, Danail Obreschkow, Nicolas Dorsaz, Philippe Kobel, Claude Nicollier

We report a fundamental study of single cavitation bubbles inside quasi-spherical water drops produced in microgravity (42nd ESA parabolic flight campaign, 8th ESA student parabolic flight campaign). High-speed imaging revealed implications of isolated, fi ...

2006

Large eddy simulation of the tip-leakage cavitating flow with an insight on how cavitation influences vorticity and turbulence

Mohamed Farhat

Cavitation within a tip leakage flow remains a challenging issue in a variety of axial hydraulic machines. It is still not possible nowadays to predict cavitation occurrence in such a flow with acceptable accuracy. In the present study, we have carried out ...

ELSEVIER SCIENCE INC2020