Publications associées à Open-loop control of a separated boundary layer

A linearized approach for the control of aerodynamic forces in flow past a square cylinder

François Gallaire, Edouard Boujo, Philippe Meliga

The analysis of Strykowski & Sreenivasan (JFM, 1990) provides experimental evidence that a small control cylinder suitably positioned in the wake of a main cylinder can alter vortex shedding close to the instability threshold. This problem was addressed fr ...

2014

Sensitivity of stochastic perturbations in a noise amplifier flow

François Gallaire, Edouard Boujo

It is a well-known fact that small-amplitude perturbations can be amplified in globally stable flows due to non-normal mechanisms. This leads in the time domain to the transient growth of some initial disturbances, and in the frequency domain to the amplif ...

2014

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

Edouard Boujo

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

From Fixed-Order Gain-Scheduling to Fixed-Structure LPV Controller Design

Zlatko Emedi

This thesis focuses on the development of some fixed-order controller design methods in the gain-scheduling/Linear Parameter Varying (LPV) framework. Gain-scheduled controllers designed using frequency-domain Single Input Single Output (SISO) models are co ...

EPFL2014

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 destabi ...

Cépaduès Editions2013

Open-loop control of noise amplification in separated boundary layers

François Gallaire, Edouard Boujo

Linear optimal gains are computed for the subcritical two-dimensional separated boundary-layer flow past a bump. Very large optimal gain values are found, making it possible for small-amplitude noise to be strongly amplified and to destabilize the flow. Th ...

2013

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

François Gallaire, Edouard Boujo

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

A real-time control system architecture for industrial power amplifiers

Faran Ahmed Qureshi

Power amplifiers are a highly important component in a range of industrial applications, such as, servo-drives, magnetic resonance imaging, energy systems, and audio. The control system for power amplifiers should satisfy a range of requirements, e. g., of ...

Ieee2013

Global modes in a confined impinging jet: application to heat transfer and control

Philippe Meliga

We investigate the stability and control of a plane, laminar jet impinging on a flat plate in a channel, a geometry used to cool down a hot wall with a cold air jet in many industrial configurations. The global stability analysis indicates that, even for a ...

Springer-Verlag2011

Feedback control of the sawtooth period through real time control of the ion cyclotron resonance frequency

Jonathan Graves

Modification of the sawtooth period through ion cyclotron resonance frequency (ICRF) heating and current drive has been demonstrated in a number of experiments. The effect has been seen to depend critically on the location of the ICRF absorption region wit ...

IOP2011

Open-loop control of a separated boundary layer

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A linearized approach for the control of aerodynamic forces in flow past a square cylinder

Sensitivity of stochastic perturbations in a noise amplifier flow

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

From Fixed-Order Gain-Scheduling to Fixed-Structure LPV Controller Design

Open-loop control of a separated boundary layer

Open-loop control of noise amplification in separated boundary layers

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

A real-time control system architecture for industrial power amplifiers

Global modes in a confined impinging jet: application to heat transfer and control

Feedback control of the sawtooth period through real time control of the ion cyclotron resonance frequency

A real-time control system architecture for industrial power amplifiers

From Fixed-Order Gain-Scheduling to Fixed-Structure LPV Controller Design

Sensitivity of stochastic perturbations in a noise amplifier flow

Global modes in a confined impinging jet: application to heat transfer and control

Open-loop control of a separated boundary layer

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

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

A linearized approach for the control of aerodynamic forces in flow past a square cylinder

Feedback control of the sawtooth period through real time control of the ion cyclotron resonance frequency

Open-loop control of noise amplification in separated boundary layers