Feedback control of unstable steady states of flow past a flat plate using reduced-order estimators

S Ahuja, CW Rowley - Journal of fluid mechanics, 2010‏ - cambridge.org
We present an estimator-based control design procedure for flow control, using reduced-
order models of the governing equations linearized about a possibly unstable steady state …

[کتاب][B] Transport barriers and coherent structures in flow data: advective, diffusive, stochastic and active methods

G Haller - 2023‏ - books.google.com
Transport barriers are observed inhibitors of the spread of substances in flows. The
collection of such barriers offers a powerful geometric template that frames the main …

Exact theory of unsteady separation for two-dimensional flows

G Haller - Journal of Fluid Mechanics, 2004‏ - cambridge.org
We use a dynamical systems approach to extend Prandtl's steady separation criterion to two-
dimensional unsteady flows with no-slip boundaries. Viewing separation profiles as non …

Optimal control of mixing in Stokes fluid flows

G Mathew, I Mezić, S Grivopoulos, U Vaidya… - Journal of Fluid …, 2007‏ - cambridge.org
Motivated by the problem of microfluidic mixing, optimal control of advective mixing in Stokes
fluid flows is considered. The velocity field is assumed to be induced by a finite set of …

Finite-time Lagrangian transport analysis: stable and unstable manifolds of hyperbolic trajectories and finite-time Lyapunov exponents

M Branicki, S Wiggins - Nonlinear Processes in Geophysics, 2010‏ - npg.copernicus.org
We consider issues associated with the Lagrangian characterisation of flow structures
arising in aperiodically time-dependent vector fields that are only known on a finite time …

Drag reduction of a bluff body using adaptive control methods

JF Beaudoin, O Cadot, JL Aider, JE Wesfreid - Physics of Fluids, 2006‏ - pubs.aip.org
A classical actuator is used to control the drag exerted on a bluff body at large Reynolds
number (R e= 20000)⁠. The geometry is similar to a backward-facing step whose separation …

Detecting vortex formation and shedding in cylinder wakes using Lagrangian coherent structures

MP Rockwood, K Taira, MA Green - AIAA journal, 2017‏ - arc.aiaa.org
The wake behind a circular cylinder is studied to investigate the complex vortex shedding
physics in the near-wake region. Both the Q criterion and a Lagrangian coherent structure …

Direct Lyapunov exponent analysis enables parametric study of transient signalling governing cell behaviour

BB Aldridge, G Haller, PK Sorger… - IEE Proceedings-Systems …, 2006‏ - IET
Computational models aid in the quantitative understanding of cell signalling networks. One
important goal is to ascertain how multiple network components work together to govern …

DG-FTLE: Lagrangian coherent structures with high-order discontinuous-Galerkin methods

DA Nelson, GB Jacobs - Journal of Computational Physics, 2015‏ - Elsevier
We present an algorithm for the computation of finite-time Lyapunov exponent (FTLE) fields
using discontinuous-Galerkin (dG) methods in two dimensions. The algorithm is designed to …

Tracking coherent structures in massively-separated and turbulent flows

M Rockwood, Y Huang, M Green - Physical Review Fluids, 2018‏ - APS
Coherent vortex structures are tracked in simulations of massively-separated and turbulent
flows. Topological Lagrangian saddle points are found using intersections of the positive …