Publications de Mohamed Farhat

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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 ...

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 ...

In the field of hydraulic power plant, the leading edge cavitation is often responsible of sever erosion which may cause a premature shutdown of energy production with costly consequences. This type of cavitation is characterized by an attached vapour cavity at the leading edge of the blades. Transient vapour vortices are generated and convected by the mean ow to the pressure recovery region where they collapse violently. The resulting water hammer pressure is responsible of material damage. In order to inv

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

Modern pump-turbines are subject to frequent switching between the pumping and generating modes with extended operation under off-design conditions. Depending on the specific speed of the pump-turbine, the discharge-speed as well as torque-speed characteristics at constant guide vanes opening can be “S-Shaped”. In this case, the machine operation may become strongly unstable at runaway speed and beyond, with a significant increase of structural vibrations and noise. In the present work, hydrodynamics of a l

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 ...

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 ...

Tip vortices generated at the tip of lifting surfaces pose significant challenges in fluid dynamics, causing induced drag, noise, and cavitation erosion risk across aerospace and hydraulic applications. Among the various mitigation strategies, porous tips have been explored with mixed results, showing limited effectiveness in diffusing concentrated vorticity. In this study, we introduce a gyroid-based porous tip as a novel passive flow control device for tip vortex mitigation. A gyroid is a triply periodic

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 ...

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 ...

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 ...

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 ...

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 ...

Mohamed Farhat

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Hemodynamic transition driven by stent porosity in sidewall aneurysms

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

Contribution à l'étude de l'érosion de cavitation : mécanismes hydrodynamiques et prédiction

BIMBAMBUM: A potential flow solver for single cavitation bubble dynamics

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

Cavitation Influence on Kármán Vortex Shedding and Induced Hydrofoil Vibrations

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

Hydro Elastic Behavior of Vibrating Blades

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

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

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

Hydrodynamics of a Pump-Turbine Operating at Off-Design Conditions in Generating Mode: Experimental Investigation

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

Numerical simulation of a collapsing bubble subject to gravity

Gyroid porous inserts as a novel flow control to mitigate tip vortex cavitation

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

Luminescence from hydrodynamic cavitation

Scaling laws for jets of single cavitation bubbles

Suppressing tip vortex cavitation by winglets

Luminescence from cavitation bubbles deformed in uniform pressure gradients