Publications related to Aerodynamics

An adjoint-based approach to the optimal control of separated flows

Flow separation is relevant to many industrial applications, since it is detrimental to the aerodynamic performance of vehicles, induces vibrations in mechanical structures, but can also contribute to improve mixing in combustion devices. In this thesis, t ...

EPFL2014

Obstacle-induced spiral vortex breakdown

Mohamed Farhat, François Gallaire, Matthieu Dreyer, Simon Pasche

An experimental investigation on vortex breakdown dynamics is performed. An adverse pressure gradient is created along the axis of a wing-tip vortex by introducing a sphere downstream of an elliptical hydrofoil. The instrumentation involves high-speed visu ...

Springer2014

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

Numerical and Experimental Investigations of an Annular Transonic Compressor Cascade Considering Leakage Flows

Peter Ott, Virginie Anne Chenaux

The accuracy of flutter or forced response analyses of turbomachinery blade assemblies strongly depends on the correct prediction of the unsteady aerodynamic loads acting on the vibrating blades. For unsteady linearized CFD solvers, the quality of the stea ...

2014

Open-loop control of a separated boundary layer

François Gallaire, Edouard Boujo

Linear optimal gains

G_{opt}(\omega)

are computed for the separated boundary-layer flow past a two-dimensional bump in the subcritical regime. Very large values are found, making it possible for small-amplitude noise to be strongly amplified and to desta ...

Elsevier France-Editions Scientifiques Medicales Elsevier2014

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

Modelling Small-Scale Drifting Snow with a Lagrangian Stochastic Model Based on Large-Eddy Simulations

Michael Lehning, Marc Parlange, Marc Diebold, Jan Overney, Gian-Duri Lieberherr

Observations of drifting snow on small scales have shown that, in spite of nearly steady winds, the snow mass flux can strongly fluctuate in time and space. Most drifting snow models, however, are not able to describe drifting snow accurately over short ti ...

Springer Verlag2014

Prediction of the hub vortex instability in a wind turbine wake: stability analysis with eddy-viscosity models calibrated on wind tunnel data

Fernando Porté Agel, François Gallaire, Giacomo Valerio Iungo, Francesco Viola

The evolution and downwind recovery of wind turbine wakes are crucial factors for the evaluation of waketo-wake interactions within a wind farm and, in turn, for the prediction of wind power harvesting. Wind turbine wakes are affected by the design of wind ...

2014

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

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An adjoint-based approach to the optimal control of separated flows

Obstacle-induced spiral vortex breakdown

Effect of trailing edge shape on hydrodynamic damping for a hydrofoil

Numerical and Experimental Investigations of an Annular Transonic Compressor Cascade Considering Leakage Flows

Open-loop control of a separated boundary layer

Mind the gap - tip leakage vortex in axial turbines

Modelling Small-Scale Drifting Snow with a Lagrangian Stochastic Model Based on Large-Eddy Simulations

Prediction of the hub vortex instability in a wind turbine wake: stability analysis with eddy-viscosity models calibrated on wind tunnel data

Vortex interaction in patches of randomly placed emergent cylinders

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

Effect of trailing edge shape on hydrodynamic damping for a hydrofoil

An adjoint-based approach to the optimal control of separated flows

Obstacle-induced spiral vortex breakdown

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

Numerical and Experimental Investigations of an Annular Transonic Compressor Cascade Considering Leakage Flows

Open-loop control of a separated boundary layer

Modelling Small-Scale Drifting Snow with a Lagrangian Stochastic Model Based on Large-Eddy Simulations

Mind the gap - tip leakage vortex in axial turbines

Prediction of the hub vortex instability in a wind turbine wake: stability analysis with eddy-viscosity models calibrated on wind tunnel data

Vortex interaction in patches of randomly placed emergent cylinders