Publications by Edouard Boujo | EPFL Graph Search

Second-order sensitivity in the cylinder wake: Optimal spanwise-periodic wall actuation and wall deformation

François Gallaire, Edouard Boujo, Andrea Fani

Two-dimensional (2D) flows can be controlled efficiently using spanwise "waviness," i.e., a control (e.g., wall blowing and suction or wall deformation) that is periodic in the spanwise direction. This study tackles the global linear stability of 2D flows ...

AMER PHYSICAL SOC2019

Revisiting the drag reduction problem using adjoint-based distributed forcing of laminar and turbulent flows over a circular cylinder

François Gallaire, Edouard Boujo, Philippe Meliga

This study assesses the ability of a sensitivity-based, span-wise homogeneous control velocity distributed at the surface of a circular cylinder to cut down the cost of reducing drag by more classical techniques, e.g., base bleed and lateral suction. At Re ...

ELSEVIER SCIENCE BV2018

Numerical simulation and sensitivity analysis of a low-Reynolds-number flow around a square cylinder controlled using plasma actuators

François Gallaire, Edouard Boujo, Philippe Meliga

Flow around a square cylinder controlled using plasma actuators (PAs) is numerically investigated by direct numerical simulation in order to clarify the most effective location of actuator installation and to elucidate the mechanism of control effect. The ...

Amer Physical Soc2017

A self-consistent formulation for the sensitivity analysis of finite-amplitude vortex shedding in the cylinder wake

François Gallaire, Edouard Boujo, Philippe Meliga

We use the adjoint method to compute sensitivity maps for the limit-cycle frequency and amplitude of the Benard von Karmzin vortex street in the wake of a circular cylinder. rfhe sensitivity, analysis is performed in the frame of the semi-linear self consi ...

Cambridge University Press2016

Pushing amplitude equations far from threshold: application to the supercritical Hopf bifurcation in the cylinder wake

François Gallaire, Edouard Boujo, Philippe Meliga, Cristobal Manuel Arratia Martinez, Vladislav Mantic Lugo

The purpose of this review article is to push amplitude equations as far as possible from threshold. We focus on the Stuart-Landau amplitude equation describing the supercritical Hopf bifurcation of the flow in the wake of a cylinder for critical Reynolds ...

Iop Publishing Ltd2016

Sensitivity and open-loop control of stochastic response in a noise amplifier flow: the backward-facing step

François Gallaire, Edouard Boujo

The two-dimensional backward-facing step flow is a canonical example of noise amplifier flow: global linear stability analysis predicts that it is stable, but perturbations can undergo large amplification in space and time as a result of non-normal effects ...

Cambridge University Press2015

Second-order sensitivity of parallel shear flows and optimal spanwise-periodic flow modifications

François Gallaire, Edouard Boujo, Andrea Fani

The question of optimal spanwise-periodic modification for the stabilisation of spanwise-invariant flows is addressed. A second-order sensitivity analysis is conducted for the linear temporal stability of parallel flows U-0 subject to small-amplitude spanw ...

Cambridge University Press2015

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

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

François Gallaire, Edouard Boujo

A variational technique is used to derive analytical expressions for the sensitivity of recirculation length to steady forcing in separated flows. Linear sensitivity analysis is applied to the two-dimensional steady flow past a circular cylinder for Reynol ...

Cambridge University Press2014

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

Edouard Boujo

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Second-order sensitivity in the cylinder wake: Optimal spanwise-periodic wall actuation and wall deformation

Revisiting the drag reduction problem using adjoint-based distributed forcing of laminar and turbulent flows over a circular cylinder

Numerical simulation and sensitivity analysis of a low-Reynolds-number flow around a square cylinder controlled using plasma actuators

A self-consistent formulation for the sensitivity analysis of finite-amplitude vortex shedding in the cylinder wake

Pushing amplitude equations far from threshold: application to the supercritical Hopf bifurcation in the cylinder wake

Sensitivity and open-loop control of stochastic response in a noise amplifier flow: the backward-facing step

Second-order sensitivity of parallel shear flows and optimal spanwise-periodic flow modifications

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

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

Open-loop control of a separated boundary layer

Second-order sensitivity in the cylinder wake: Optimal spanwise-periodic wall actuation and wall deformation

Numerical simulation and sensitivity analysis of a low-Reynolds-number flow around a square cylinder controlled using plasma actuators

Revisiting the drag reduction problem using adjoint-based distributed forcing of laminar and turbulent flows over a circular cylinder

A self-consistent formulation for the sensitivity analysis of finite-amplitude vortex shedding in the cylinder wake

Sensitivity and open-loop control of stochastic response in a noise amplifier flow: the backward-facing step

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

Second-order sensitivity of parallel shear flows and optimal spanwise-periodic flow modifications

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

Open-loop control of a separated boundary layer

Pushing amplitude equations far from threshold: application to the supercritical Hopf bifurcation in the cylinder wake