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LES investigation of the influence of cavitation on flow patterns in a confined tip-leakage flow

Publications associées (45)

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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

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

Stability analysis of boundary layers controlled by miniature vortex generators

Lorenzo Siconolfi

It is currently known that Tollmien–Schlichting (TS) waves can be attenuated by the introduction of spanwise mean velocity gradients in an otherwise two-dimensional boundary layer (BL). The stabilizing effect, associated with an extra turbulence production ...

Cambridge University Press2015

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

Turbulent-laminar patterns in plane Poiseuille flow

Tobias Schneider, Tobias Klaus Kreilos

Turbulent-laminar banded patterns in plane Poiseuille flow are studied via direct numerical simulations in a tilted and translating computational domain using a parallel version of the pseudospectral code Channelflow. 3D visualizations via the streamwise v ...

Amer Inst Physics2014

Vortex interaction in patches of randomly placed emergent cylinders

Anton Schleiss, Mário Jorge Rodrigues Pereira Da Franca, Ana Margarida Da Costa Ricardo

The flow field of multiple-cylinder configurations exhibits complex interactions between shear layers, vortexes and wakes. For high stem-Reynolds numbers, the flow is turbulent and, low and intermediate areal number-densities of cylinders, and turbulence i ...

A.J. Schleiss, G. De Cesare, M. Franca, M. Pfister2014

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

Mohamed Farhat, Cécile Münch-Alligné, Matthieu Dreyer

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

Vortical Flow Patterns for High Lift for High Speed Aircraft Concepts

Pénélope Leyland, Michele Gaffuri

Enhancing detached vortical flow over leading edges and flap surfaces allow high lift configurations in critical regimes of take-off and acceleration. In the context of the FP6 Environmentally Friendly High Speed Aircraft project HISAC, future high speed a ...

2013

Influence of confinement on obstacle-free turbulent wakes

François Gallaire, Luca Biancofiore

Large-eddy simulations (LESs) of obstacle-free wakes, in a channel like geometry with an homogeneous transverse direction, are carried out in order to investigate the influence of confinement on turbulent wakes. The numerical solver makes use of a multi-do ...

Elsevier2012

The onset of dynamic stall revisited

Karen Ann J Mulleners

Dynamic stall on a helicopter rotor blade comprises a series of complex aerodynamic phenomena in response to the unsteady change of the blade's angle of attack. It is accompanied by a lift overshoot and delayed massive flow separation with respect to stati ...

2012