Publications related to Complexity of localised coherent structures in a boundary-layer flow

Forced reattachment in separated flows: a variational approach to recirculation length reduction

Sensitivity analysis is used to design an open-loop control for separated flows. The length of the recirculation region

l_c

is expressed as a cost functional, and its sensitivity to actuation is derived analytically. This analysis allows to identify regi ...

2013

Experimental study from linear to chaotic regimes on a terahertz-frequency gyrotron oscillator

Stefano Alberti, Minh Quang Tran, Jean-Philippe Ansermet, Jean-Philippe Hogge, Damien Fasel, Jérémie Dubray, Philippe Cuanillon, Alessandro Macor, Miguel Da Silva

Basic wave-particle interaction dynamics from linear to chaotic regimes is experimentally studied on a frequency tunable gyrotron generating THz radiation in continuous mode (200W) at 263GHz which will be used for dynamic nuclear polarization nuclear magne ...

American Institute of Physics2012

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

Correcting hot-wire measurements of stream-wise turbulence intensity in boundary layers

Peter Monkewitz

The current experimental activity aimed at resolving the scaling of stream-wise turbulence intensity profiles (uu) over bar (+)(y(+)) with Reynolds number in turbulent flat plate boundary layers has brought the largely unresolved issue of correcting system ...

2010

Open-loop control of compressible afterbody flows using adjoint methods

Philippe Meliga

The flow past an axisymmetric body is generically unstable to a steady and a time-periodic global instability, the latter being thought to lead the low-frequency unsteadiness of the wake even at larger Reynolds numbers. The present paper examines how the g ...

2010

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

An experimental study of coherent structures, secondary currents and surface boils and their interrelation in open-channel flow

Ismail Albayrak

River and open-channel flows are free surface boundary layer flows with complex 3D, large-scale, turbulent structures. The study of 2D and 3D large-scale turbulent flow structures is a great challenge for physicists, mathematicians and engineers from such ...

EPFL2008

Dynamical systems and the transition to turbulence in linearly stable shear flows

Tobias Schneider

Plane Couette flow and pressure-driven pipe flow are two examples of flows where turbulence sets in while the laminar profile is still linearly stable. Experiments and numerical studies have shown that the transition has features compatible with the format ...

2008

Hydrofoil Roughness Effects on von Kármán Vortex Shedding

François Avellan, Mohamed Farhat, Philippe Ausoni

The shedding process of the von Kármán vortices is shown to be highly related to the state of the boundary layer over the entire hydrofoil: The selected hydrofoil has a laminar-turbulent boundary layer transition at mid-chord for an incidence angle of 0° a ...

2007

Cavitation in Kármán Vortex Shedding from 2D Hydrofoil: Wall Roughness effects

François Avellan, Mohamed Farhat, Philippe Ausoni

The present study deals with the shedding process of the Kármán vortices in the wake of a NACA0009 hydrofoil at high Reynolds number. This research addresses the effects of the foil leading edge roughness on the wake dynamic with a special focus on the vor ...

2007

Complexity of localised coherent structures in a boundary-layer flow

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Forced reattachment in separated flows: a variational approach to recirculation length reduction

Experimental study from linear to chaotic regimes on a terahertz-frequency gyrotron oscillator

Effect of Hydrofoil Trailing Edge Geometry on the Wake Dynamics

Correcting hot-wire measurements of stream-wise turbulence intensity in boundary layers

Open-loop control of compressible afterbody flows using adjoint methods

Turbulent vortex shedding from a blunt trailing edge hydrofoil

An experimental study of coherent structures, secondary currents and surface boils and their interrelation in open-channel flow

Dynamical systems and the transition to turbulence in linearly stable shear flows

Hydrofoil Roughness Effects on von Kármán Vortex Shedding

Cavitation in Kármán Vortex Shedding from 2D Hydrofoil: Wall Roughness effects

Hydrofoil Roughness Effects on von Kármán Vortex Shedding

An experimental study of coherent structures, secondary currents and surface boils and their interrelation in open-channel flow

Turbulent vortex shedding from a blunt trailing edge hydrofoil

Open-loop control of compressible afterbody flows using adjoint methods

Correcting hot-wire measurements of stream-wise turbulence intensity in boundary layers

Effect of Hydrofoil Trailing Edge Geometry on the Wake Dynamics

Forced reattachment in separated flows: a variational approach to recirculation length reduction

Dynamical systems and the transition to turbulence in linearly stable shear flows

Experimental study from linear to chaotic regimes on a terahertz-frequency gyrotron oscillator

Cavitation in Kármán Vortex Shedding from 2D Hydrofoil: Wall Roughness effects