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Mohamed Farhat

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Related publications (118)

Page 1 of 6

Hemodynamic transition driven by stent porosity in sidewall aneurysms

Mohamed Farhat, Pierre Bouillot

The healing process of intracranial aneurysms (IAs) treated with flow diverter stents (FDSs) depends on the IA flow modifications and on the epithelization process over the neck. In sidewall IA models with straight parent artery, two main hemodynamic regim ...

Elsevier2015

Pump-Turbine Rotor-Stator Interactions in Generating Mode: Pressure Fluctuation in Distributor Channel

François Avellan, Mohamed Farhat, Amirreza Zobeiri

Investigation of the rotor-stator interactions of a reduced-scale model 0.19 ν= pump-turbine in generating mode is presented for the maximum discharge operating condition. This operating point is chosen in order to have the most important rotor-stator inte ...

International Association For Hydraulic Research2006

Fluid-structure coupling for an oscillating hydrofoil

François Avellan, Mohamed Farhat, Cécile Münch-Alligné

Fluid-structure investigations in hydraulic machines using coupled simulations are particularly time-consuming. In this study, an alternative method is presented that linearizes the hydrodynamic load of a rigid, oscillating hydrofoil. The hydrofoil, which ...

Elsevier2010

Methodologies to assess blood flow in cerebral aneurysms: Current state of research and perspectives

Nikolaos Stergiopoulos, Mohamed Farhat, Philippe Reymond

With intracranial aneurysms disease bringing a weakened arterial wall segment to initiate, grow and potentially rupture an aneurysm, current understanding of vessel wall biology perceives the disease to follow the path of a dynamic evolution and increasing ...

2009

BIMBAMBUM: A potential flow solver for single cavitation bubble dynamics

Mohamed Farhat, Davide Bernardo Preso, Armand Baptiste Sieber

In the absence of analytical solutions for the dynamics of non -spherical cavitation bubbles, we have implemented a numerical simulation solver based on the boundary integral method (BIM) that models the behavior of a single bubble near an interface betwee ...

Elsevier2024

Cavitation Influence on Kármán Vortex Shedding and Induced Hydrofoil Vibrations

François Avellan, Mohamed Farhat

The present study deals with the shedding process of the von Kármán vortices at the trailing edge of a 2D hydrofoil at high Reynolds number. This research focuses mainly on the effects of cavitation and fluid-structure interaction on the mechanism of the v ...

2007

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

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

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

Hydro Elastic Behavior of Vibrating Blades

François Avellan, Mohamed Farhat, Cécile Münch-Alligné

Fluid-structure investigations in hydraulic machines using coupled simulations are extremely time-consuming; therefore we develop an alternative method. In this paper, a model is proposed to predict fluid-structure coupling by linearizing the hydrodynamic ...

International Association For Hydraulic Research2008

Unsteady CFD Prediction of von Kármán Vortex Shedding in Hydraulic Turbine Stay Vanes

François Avellan, Mohamed Farhat

All hydraulic turbines containing a casing with stay vanes face the potential dynamic problem of stay vane von Kármán vortex shedding. For hydraulic efficiency purposes the stay vanes tend to be relatively slender in the direction normal to the flow thus b ...

2007

Evidence for hydrogen generation in laser- or spark-induced cavitation bubbles

Mohamed Farhat, Marc Tinguely

The growing use of focused lasers or electric sparks to generate cavitation bubbles raises concerns about the possible alteration of gas content during the initiation process and its effect on bubble dynamics. We provide experimental evidence that hydrogen ...

American Institute of Physics2013

Energy partition at the collapse of spherical cavitation bubbles

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

Spherically collapsing cavitation bubbles produce a shock wave followed by a rebound bubble. Here we present a systematic investigation of the energy partition between the rebound and the shock. Highly spherical cavitation bubbles are produced in micrograv ...

American Physical Society2012

The detection of cavitation in hydraulic machines by use of ultrasonic signal analysis

Mohamed Farhat, Pascal Damian Odermatt, Michelle Susanne Frei

This presentation describes an experimental approach for the detection of cavitation in hydraulic machines by use of ultrasonic signal analysis. Instead of using the high frequency pulses (typically 1MHz) only for transit time measurement different other s ...

International Association For Hydraulic Research2014

Vapor compression and energy dissipation in a collapsing laser-induced bubble

Mohamed Farhat, Danail Obreschkow, Davide Bernardo Preso, Armand Baptiste Sieber

The composition of the gaseous phase of cavitation bubbles and its role on the collapse remains to date poorly understood. In this work, experiments of single cavitation bubbles in aqueous ammonia serve as a novel approach to investigate the effect of the ...

Aip Publishing2024

Plasma-based identification of gases in a laser-induced cavitation bubble

Mohamed Farhat

This study presents a general methodology and an experimental approach to identify the gas components within laser-induced cavitation bubbles. A needle electrode inside the cavitation bubble, which introduces low electric energy into the bubble, produces a ...

AIP Publishing2023

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

Experimental Evidence of Rotating Stall in a Pump-Turbine at Off-Design Conditions in Generating Mode

François Avellan, Mohamed Farhat, Vlad Hasmatuchi, Steven Roth

An experimental investigation of the rotating stall in reduced scale model of a low specific speed radial pump-turbine at runaway and turbine brake conditions in generating mode is achieved. Measurements of wall pressure in the stator are performed along w ...

American Society of Mechanical Engineers2011

Luminescence from hydrodynamic cavitation

Mohamed Farhat

The majority of the research on cavitation luminescence has focused on the sonoluminescence or chemiluminescence generated by cavitation induced through ultrasound, with a lesser body of work on the luminescence induced by laser- or spark induced cavitatio ...

2010

Scaling laws for jets of single cavitation bubbles

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

Suppressing tip vortex cavitation by winglets

Mohamed Farhat, Ali Amini, Martino Reclari

Despite the numerous remedies prescribed so far, tip vortex cavitation (TVC) remains a major issue in design and operation of diverse applications. In this paper, we experimentally investigate the effectiveness of winglets in suppressing TVC. An elliptical ...

SPRINGER2019

Luminescence from cavitation bubbles deformed in uniform pressure gradients

Mohamed Farhat, Philipp Kobel, Danail Obreschkow, Philippe 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