Publications associées à Hydroptère

Vortex shedding from a composite hydrofoil: Experimental evidence of a novel "partial lock-in"

Mohamed Farhat, Thomas Antoine Nicolas Berger, Qin Wu, Yunqing Liu

Lock-in is of great importance in many engineering applications due to its practical implications for structural safety. The influence of composite bend-twist coupling on the wake dynamics and vortex-induced vibration around a carbon fiber composite hydrof ...

Aip Publishing2023

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

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

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

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

Turbulent vortex shedding from a blunt trailing edge hydrofoil

Philippe Ausoni

Placed in a fluid stream, solid bodies can exhibit a separated flow that extends to their wake. The detachment of the boundary layer on both upper and lower surfaces forms two shear layers which generate above a critical value of Reynolds number a periodic ...

EPFL2009

Numerical investigations of fluid structure coupling: oscillating hydrofoil

François Avellan, Olivier Braun, Cécile Münch-Alligné

This paper presents an investigation of the hydro elastic behavior of vibrating blades in hydraulic machines, which is of strong interest for turbo machinery applications. As a representative case study for vibrating blade in hydraulic machines, a NACA 000 ...

2008

Cavitation Influence on Kármán Vortex Shedding and Induced Hydrofoil Vibrations

François Avellan, Mohamed Farhat, Philippe Ausoni, Eduard Egusquiza

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

Cavitation in Kármán Vortices and Flow Induced Vibrations

François Avellan, Mohamed Farhat, Philippe Ausoni

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

Etude physique de l'apparition et du développement de la cavitation sur une aube isolée

Mohamed Faiçal Guennoun

The physical mechanism that governs the incipience and development of leading edge cavitation on hydrofoils is still not fully understood. It involves several parameters such as the pressure level, the nuclei content, the surface roughness and the boundary ...

EPFL2006

Kármán vortex shedding in the wake of a 2D hydrofoil: Measurement and numerical simulation

François Avellan, Mohamed Farhat, Philippe Ausoni, Youcef Ait Bouziad

The present study deals with the shedding process of the Kármán vortices at the trailing edge of a 2D hydrofoil at high Reynolds numbers. Investigations are performed in order to evaluate the ability of an unsteady numerical simulation to accurately reprod ...

2006

Cavitation effects on fluid-structure interaction in the case of a 2D hydrofoil

François Avellan, Philippe Ausoni, Mohamed Farhat

In the present study, we have carried out an experimental investigation on the fluid-structure interaction caused by Karman vortices in the wake of a truncated 2D hydrofoil. The instrumentation involves a high frequency accelerometer and high speed visuali ...

2005

Physical modelling of leading edge cavitation : computational methodologies and application to hydraulic machinery

Youcef Ait Bouziad

Cavitation is usually the main physical phenomenon behind performance alterations in hydraulic machinery. For this reason, it is crucial to accurately predict its inception and development and to highlight a comprehensive relation between the cavitation de ...

EPFL2005

Etude de l'influence des instationnarités des écoulements sur le développement de la cavitation

Jean-François Caron

Flows in hydraulic machinery show interactions between guiding and rotating components. The wakes of the fixed components will be part responsible for the pressure fluctuations sensed on the blades. Those fluctuations become more important when the distanc ...

EPFL2002