Publications de Matthieu Dreyer

Production flexibility of small run-of-river power plants: KWGO smart-storage case study

Pedro Filipe De Almeida Manso, Steve Crettenand, Matthieu Dreyer, Vlad Hasmatuchi, Jessica Zordan, Siamak Alimirzazadeh

In the framework of the new Swiss feed-in-tariff system for Small Hydropower Plants (SHP), the aim of the SmallFLEX project, led by HES-SO Valais and performed in collaboration with EPFL, WSL, EAWAG, PVE and FMV, is to show how SHP can provide winter peak ...

IOP PUBLISHING LTD2021

On the physical mechanism of tip vortex cavitation hysteresis

Mohamed Farhat, Martino Reclari, Matthieu Dreyer, Ali Amini

Inception and desinence thresholds of tip vortex cavitation (TVC), generated by an elliptical NACA 16-020 hydrofoil, are measured at different flow conditions for various gas contents. It is observed that TVC often disappears at cavitation indices signific ...

SPRINGER2019

Roll-up region of tip vortex: numerical investigation

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

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 PUBLISHING LTD2019

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

RANS and LES computations of the tip-leakage vortex for different gap widths

Mohamed Farhat, Matthieu Dreyer

In hydraulic turbines, the tip-leakage vortex is responsible for flow instabilities and for promoting erosion due to cavitation. To better understand the tip vortex flow, Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) computations a ...

Taylor & Francis2015

Mind The Gap : Tip Leakage Vortex Dynamics and Cavitation in Axial Turbines

Matthieu Dreyer

The tip leakage vortex (TLV), which develops in the clearance between the blade tip and the casing of axial turbomachines, appears in many industrial applications, such as air transportation, space rockets and hydraulic machines. In the latter, cavitation ...

EPFL2015

RANS computations of tip vortex cavitation

Mohamed Farhat, Matthieu Dreyer

Some two-dimensional (2D) exfoliated zeolites are single- or near single-unit cell thick silicates that can function as molecular sieves. Although they have already found uses as catalysts, adsorbents and membranes precise determination of their thickness ...

Institute of Physics2015

Mind the gap - tip leakage vortex in axial turbines

Mohamed Farhat, Matthieu Dreyer

The tendency of designing large Kaplan turbines with a continuous increase of output power is bringing to the front the cavitation erosion issue. Due to the flow in the gap between the runner and the discharge ring, axial turbine blades may develop the so ...

Iop Publishing Ltd2014

Effect of trailing edge shape on hydrodynamic damping for a hydrofoil

Mohamed Farhat, Matthieu Dreyer, Zhifeng Yao

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

Mind the gap: a new insight into the tip leakage vortex using stereo-PIV

Mohamed Farhat, Matthieu Dreyer, Cécile Münch-Alligné

The tip leakage vortex (TLV), which develops in the clearance between the rotor and the stator of axial hydro turbines, has been studied for decades. Yet, many associated phenomena are still not understood. For instance, it remains unclear how the clearanc ...

Springer2014

Interaction of a pulsating vortex rope with the local velocity field in a Francis turbine draft tube

François Avellan, Andres Müller, Steven Roth, Christian Landry, Matthieu Dreyer, Alberto Bullani, Arthur Tristan Favrel

Acoustic resonances in Francis turbines often define undesirable limitations to their operating ranges at high load. The knowledge of the mechanisms governing the onset and the sustenance of these instabilities in the swirling flow leaving the runner is es ...

IOP science2013

Hydrodynamic stress in orbitally shaken bioreactors

Florian Maria Wurm, Lucia Baldi Unser, Alfio Quarteroni, Mohamed Farhat, Marco Discacciati, David Hacker, Stéphanie Tissot, Martino Reclari, Samuel Quinodoz, Matthieu Dreyer, Dominique Terry Monteil Jr

2011

Efficient and reproducible mammalian cell bioprocesses without probes and controllers?

Florian Maria Wurm, Lucia Baldi Unser, Mohamed Farhat, David Hacker, Stéphanie Tissot, Martino Reclari, Matthieu Dreyer, Agata Oberbek

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