Publications associées à Second-order adjoint-based sensitivity for hydrodynamic stability and control

An indefinite variant of LOBPCG for definite matrix pencils

In this paper, we propose a novel preconditioned solver for generalized Hermitian eigenvalue problems. More specifically, we address the case of a definite matrix pencil , that is, A, B are Hermitian and there is a shift such that is definite. Our new meth ...

Springer2014

Nonlinear Eigenvalue Problems With Specified Eigenvalues

Daniel Kressner

This work considers eigenvalue problems that are nonlinear in the eigenvalue parameter. Given such a nonlinear eigenvalue problem T, we are concerned with finding the minimal backward error such that T has a set of prescribed eigenvalues with prescribed al ...

Siam Publications2014

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

Soft Constrained Model Predictive Control With Robust Stability Guarantees

Colin Neil Jones, Melanie Nicole Zeilinger

Soft constrained model predictive control (MPC) is frequently applied in practice in order to ensure feasibility of the optimization during online operation. Standard techniques offer global feasibility by relaxing state or output constraints, but cannot e ...

Institute of Electrical and Electronics Engineers2014

Low-Rank Tensor Methods With Subspace Correction For Symmetric Eigenvalue Problems

Daniel Kressner, André Uschmajew, Michael Maximilian Steinlechner

We consider the solution of large-scale symmetric eigenvalue problems for which it is known that the eigenvectors admit a low-rank tensor approximation. Such problems arise, for example, from the discretization of high-dimensional elliptic PDE eigenvalue p ...

Siam Publications2014

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

On A Perturbation Bound For Invariant Subspaces Of Matrices

Daniel Kressner

Given a nonsymmetric matrix A, we investigate the effect of perturbations on an invariant subspace of A. The result derived in this paper differs from Stewart's classical result and sometimes yields tighter bounds. Moreover, we provide norm estimates for t ...

Siam Publications2014

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

François Gallaire, Edouard Boujo, Andrea Fani

We perform a second-order sensitivity analysis of the linear temporal stability of a parallel flow subject to small spanwise periodic modification. The need for a second-order analysis results from the fact that spanwise-periodic flow modifications have a ...

2014

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

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

Second-order adjoint-based sensitivity for hydrodynamic stability and control

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An indefinite variant of LOBPCG for definite matrix pencils

Nonlinear Eigenvalue Problems With Specified Eigenvalues

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

Soft Constrained Model Predictive Control With Robust Stability Guarantees

Low-Rank Tensor Methods With Subspace Correction For Symmetric Eigenvalue Problems

Open-loop control of a separated boundary layer

On A Perturbation Bound For Invariant Subspaces Of Matrices

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

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

Open-loop control of noise amplification in separated boundary layers

Soft Constrained Model Predictive Control With Robust Stability Guarantees

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

An indefinite variant of LOBPCG for definite matrix pencils

Nonlinear Eigenvalue Problems With Specified Eigenvalues

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

Open-loop control of a separated boundary layer

Open-loop control of noise amplification in separated boundary layers

On A Perturbation Bound For Invariant Subspaces Of Matrices

Low-Rank Tensor Methods With Subspace Correction For Symmetric Eigenvalue Problems

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