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Mohamed Farhat

Cette personne a quitté l’EPFL

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Publications associées (118)

Page 5 sur 6

Dynamics and Intensity of Erosive Partial Cavitation

François Avellan, Mohamed Farhat

An experimental work has been carried out to investigate the dynamic behavior and the intensity of erosive partial cavitation on a 2-D hydrofoil. Both sheet (stable) and cloud (unstable) cavitation have been tested in a cavitation tunnel for various free s ...

2007

The Effects of a Tripped Turbulent Boundary Layer on Vortex Shedding from a Blunt Trailing Edge Hydrofoil

François Avellan, Mohamed Farhat, Amirreza Zobeiri

Experiments on vortex shedding from a blunt trailing edge symmetric hydrofoil operating at zero angle of attack in a uniform high speed flow, Re-h = 16.1 . 10(3) - 96.6 . 10(3), where the reference length h is the trailing edge thickness, are reported. The ...

2012

A review of cavitation in tip-leakage flow and its control

Mohamed Farhat

The tip-leakage vortex (TLV) cavitation is a challenging issue for a variety of axial hydraulic turbines and pumps from both technical and scientific viewpoints. The flow characteristics of the TLV cavitation were widely studied in the past decades, but th ...

SPRINGER2021

Suppressing tip-leakage vortex cavitation by overhanging grooves

Mohamed Farhat

In the present paper, a new control method for tip-leakage vortex (TLV) cavitation is proposed. This method, which combines the effects of grooves and winglets, is made of overhanging grooves (OHGs) fitted at the tip of a hydrofoil. Experimental and numeri ...

SPRINGER2020

Radial Shock Wave Devices Generate Cavitation

Mohamed Farhat, Philipp Kobel, Philippe 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

Hysteresis phenomena in hydraulic measurement

Mohamed Farhat

Hysteresis phenomena demonstrate the lag between the generation and the removal of some physical phenomena. This paper studies the hysteresis phenomena of the head-drop in a scaled model pump turbine using experiment test and CFD methods. These lag is indu ...

IOP Publishing2013

Experimental Investigation of Flow Instabilities and Rotating Stall in a High-Energy Centrifugal Pump Stage

François Avellan, Maher Kayal, Mohamed Farhat, Philippe Dupont, Laurent Fabre

In centrifugal pumps, the interaction between the rotating impeller and the stationary diffuser generates specific pressure fluctuation patterns. When the pump is operated at off design conditions, these pressure fluctuations increase. The resulting rise o ...

ASME2009

Experimental investigation of a pump-turbine at off-design operating conditions

François Avellan, Mohamed Farhat, Pierre Maruzewski, Vlad Hasmatuchi

Pumped storage power plants are key components for the development of new renewable CO2-free primary energies and the security enhancement of electricity supply. They also offer interesting business opportunities in nowadays liberalized electricity market. ...

Brno University of Technology2009

Experimental investigation of added mass effects on a hydrofoil under cavitation conditions

Mohamed Farhat

The influence of leading edge sheet cavitation and supercavitation on the added mass effects experienced by a 2-D NACA0009 truncated hydrofoil has been experimentally investigated in a hydrodynamic tunnel. A non-intrusive excitation and measuring system ba ...

Elsevier2013

Cavitation in Kármán Vortices and Flow Induced Vibrations

François Avellan, Mohamed Farhat

The shedding process of the Kármán vortices at the trailing edge of a 2D hydrofoil at high Reynolds numbers is investigated. The focus is put on the effect of the cavitation on the vortex street morphology. A direct insight is also provided on the role of ...

2006

Near-wall hemodynamic parameters quantification in in vitro intracranial aneurysms with 7 T PC-MRI

Antoine Michel Sache, Mohamed Farhat, Philippe Reymond

ObjectiveWall shear stress (WSS) and its derived spatiotemporal parameters have proven to play a major role on intracranial aneurysms (IAs) growth and rupture. This study aims to demonstrate how ultra-high field (UHF) 7 T phase contrast magnetic resonance ...

SPRINGER2023

One-Dimensional Analysis of Full Load Draft Tube Surge

François Avellan, Mohamed Farhat, Christophe Nicolet

One-dimensional stability analysis of a hydraulic system composed of a penstock, a runner, and a draft tube was carried out to determine the cause of the full load draft tube surge. It is assumed that the cavity volume at the runner exit is a function of t ...

2008

Effect of trailing edge shape on hydrodynamic damping for a hydrofoil

Zhifeng Yao, Mohamed Farhat, Matthieu Dreyer

Flow induced vibration on a hydrofoil may be significantly reduced with a slight modification of the trailing edge without alteration of the hydrodynamic performance. Particularly, the so called Donaldson trailing edge shape gave remarkable results and is ...

Elsevier2014

2D Oscillating Hydrofoil

François Avellan, Mohamed Farhat, Cécile Münch-Alligné

This paper presents a validation of numerical simulations in case of a forced oscillating hydrofoil. As a representative case study for vibrating blade in hydraulics machines, a 2D NACA 0009 oscillating hydrofoil is considered. Pressure coefficients from e ...

2007

Onset of Flow Separation Phenomenon in a Low-Specific Speed Centrifugal Pump Impeller

Mohamed Farhat

The efficiency of centrifugal pumps drops sharply when the flowrate is reduced below a threshold value. This is due to a profound change in the flow structure, characterized by a large of portion flow separation near the impeller blades and the formation o ...

ASME2023

High Speed Flow Visualisation of an Impinging Jet on a Pelton Turbine Bucket

François Avellan, Mohamed Farhat, Alexandre Perrig

This paper deals with flow investigations using endoscopes in a single-injector reduced scale Pelton turbine performed with a CMOS high-speed camera. Both onboard and external visualizations techniques of the flow in a bucket are presented. The flow observ ...

ASME2007

A new Euler-Lagrangian cavitation model for tip-vortex cavitation with the effect of non-condensable gas

Mohamed Farhat

Numerical simulation of tip vortex cavitation (TVC) remains a challenging task in a variety of applica-tions, such as axial turbines and pumps as well as marine propellers. Although it is well known that TVC is highly sensitive to gas content, be it dissol ...

PERGAMON-ELSEVIER SCIENCE LTD2021

Hydrodynamics of a Pump-Turbine at Off-Design Operating Conditions: Numerical Simulation

François Avellan, Mohamed Farhat, Vlad Hasmatuchi, Steven Roth

Flow numerical simulations in a low specific speed radial pump-turbine scale model are performed to investigate off-design operating conditions in generating mode. The Best Efficiency Point (BEP) and the runaway operating conditions at 10° guide vanes open ...

2011

Cavitation bubble dynamics and microjet atomization near tissue-mimicking materials

Mohamed Farhat, Davide Bernardo Preso, Armand Baptiste Sieber

In recent years, considerable interest has been devoted to the interactions between cavitation bubbles and tissue-mimicking materials due to their promising applications in medicine and biomedical sciences. The strong fluid-structure interaction between a ...

AIP Publishing2023

A self-assembled three-dimensional cloak in the visible

Mohamed Farhat, Toralf Scharf

An invisibility cloak has been designed, realized and characterized. The cloak hides free-standing sub-wavelength three-dimensional objects at the short wavelength edge of the visible spectrum. By a bottom-up approach the cloak was self-assembled around th ...

Nature Publishing Group2013