Publications de Amirreza Zobeiri

Boundary layer effects on the vortex shedding in a Donaldson-type hydrofoil

François Avellan, Mohamed Farhat, Eduard Egusquiza, Amirreza Zobeiri

Structure Interaction (FSI) phenomena is becoming a relevant study field for the design or revamping of hydropower plants. The generalized trend of increasing flow rates and reducing rotor blades/stay vanes thickness in order to improve the efficiency of t ...

International Association For Hydraulic Research2014

Effect of Hydrofoil Trailing Edge Geometry on the Wake Dynamics

Amirreza Zobeiri

In the present study, the effect of a hydrofoil trailing edge shape on the wake dynamic and its interaction with the mechanical structure is investigated. This would help better describe the physical reasons for vibration reduction when using oblique and D ...

EPFL2012

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

François Avellan, Mohamed Farhat, Philippe Ausoni, 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

How oblique trailing edge of a hydrofoil reduces the vortex-induced vibration

François Avellan, Mohamed Farhat, Philippe Ausoni, Amirreza Zobeiri

The effect of hydrofoil trailing edge shape on the wake dynamic and flow induced vibration is investigated at high Reynolds number, Re = 0.5 x 10(6)-2.9 x 10(6). Two NACA 0009 hydrofoils with blunt and oblique trailing edges are tested. The velocity field ...

Elsevier2012

On the upper part load vortex rope in Francis turbine: Experimental investigation

François Avellan, Christophe Nicolet, Amirreza Zobeiri, Pierre Maruzewski

The swirling flow developing in Francis turbine draft tube under part load operation leads to pressure fluctuations usually in the range of 0.2 to 0.4 times the runner rotational frequency resulting from the so-called vortex breakdown. For low cavitation n ...

International Association For Hydraulic Research2010

Experimental investigation of the vortex shedding dynamic in the wake of oblique and blunt trailing edge hydrofoils using PIV-POD method

François Avellan, Mohamed Farhat, Philippe Ausoni, Amirreza Zobeiri

This paper presents an experimental investigation of the vortex shedding in the wake of blunt and oblique trailing edge hydrofoils at high Reynolds number, Re=5 10 5 - 2.9 10 6. The velocity field in the wake is surveyed with the help of Particle-Image-Vel ...

American Soc Mechanical Engineers2010

Vortex shedding from blunt and oblique trailing edge hydrofoils

François Avellan, Mohamed Farhat, Philippe Ausoni, Amirreza Zobeiri

The phenomenon of vortex shedding behind a hydrofoil is an important issue from both scientific and technical point of view. The resulting fluctuating forces may lead to excessive vibrations and premature cracks in the hydraulic machines. According to prev ...

Brno university of technology2009

Investigations of time dependent flow phenomena in a turbine and a pump-turbine of Francis type : rotor-stator interactions and precessing vortex rope

Amirreza Zobeiri

The present work deals with time dependent phenomena, which develop in turbines and pump turbines of Francis type. These phenomena may cause serious damages to hydropower plant. The overall objective of this study is to bring a better understanding of two ...

EPFL2009

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