Robust control of plane Poiseuille flow

Baramov, L.; Tutty, O.R.; Rogers, Eric

doi:10.2514/6.2000-2684

Cited by 9 publications

(4 citation statements)

References 7 publications

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“…In Bewley & Liu (1998), H ∞ compensation was calculated for one wavenumber pair of the present problem, and was shown to provide a significantly better response to worst-case perturbations in the linear setting than optimal H 2 compensation. A similar study was also performed by Baramov et al (2000).…”

Section: H ∞ Controlmentioning

confidence: 74%

“…In Lee et al (2001) extension of the two-dimensional controller to a threedimensional one by augmenting an ad hoc scheme in the third direction is suggested and tested in a turbulent flow. The streamfunction formulation was also used by Baramov et al (2000) to apply robust (H ∞ ) control to the two-dimensional fluid system with multi-wavenumber control, accounting for effects of localized actuation and sensing. A complete formulation for model-based control of three-dimensional perturbations is presented in Bewley & Liu (1998).…”

Section: Flow Control Backgroundmentioning

confidence: 99%

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Linear feedback control and estimation of transition in plane channel flow

2003

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Modern linear control theory has recently been established as a viable tool for developing effective, spatially localized convolution kernels for the feedback control and estimation of linearized Navier-Stokes systems. In the present paper, the effectiveness of these kernels for significantly expanding the basin of attraction of the laminar state in a subcritical nonlinear channel flow system is quantified using direct numerical simulations for a range of Reynolds numbers (Re C L = 2000, 3000 and 5000) and for a variety of initial conditions of physical interest. This is done by quantifying the change in the transition thresholds (see Reddy et al. 1998) when feedback control is applied. Such transition thresholds provide a relevant measure of performance for transition control strategies even in the nonlinear regime. Initial flow perturbations with streamwise vortices, oblique waves, and random excitations over an array of several Fourier modes are considered. It is shown that the minimum amplitude of these initial flow perturbations that is sufficient to excite nonlinear instability, and thereby promote transition to turbulence, is significantly increased by application of the control feedback. The kernels used to apply the feedback are found to decay exponentially with distance far from the origin, as predicted by the analysis of Bamieh, Paganini & Dahleh (2002). In the present paper, it is demonstrated via numerical simulation that truncation of these spatially localized convolution kernels to spatially compact kernels with finite non-zero support does not significantly degrade the effectiveness of the control feedback. In addition to the new state-feedback control results, exponential convergence of a localized physical-space state estimator with wall measurements is also demonstrated. The estimator and the full-state feedback controller are then combined to obtain a wall-information-based linear compensator. The compensator performance is also quantified, and key issues related to improving the performance of this compensator, which is degraded compared with the full-state feedback controller, are discussed.

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Section: H ∞ Controlmentioning

confidence: 74%

Section: Flow Control Backgroundmentioning

confidence: 99%

Linear feedback control and estimation of transition in plane channel flow

2003

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“…Some success using this approach has been reported in the last decade, aiming at suppressing disturbances (e.g., to delay transition) in a laminar channel [6,10,44] or in a laminar boundary layer [37], or reducing skin-friction drag of turbulent channel flows [37,38,55]. Some implications of applying a linear approach to nonlinear wall-bounded flows were discussed by Kim and Lim [49].…”

Section: Active Control Of Complex Flowmentioning

confidence: 99%

Optimal Controller for Turbulent Flow Over an Airfoil

Kim¹

2006

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to the Department of Defense. Executive Services and Communications Directorate (0704-0188t.Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION. REPORT DATE (DD-MM-YYYY)2. REPORT TYPE 3. DATES COVERED (From -To) The objectives of this project are twofold: to develop a detached-eddy simulation (DES) technique for turbulent flows past an airfoil at a high angle of attack, and to explore new control strategies for the separated flow, utilizing modem control theories. A system identification approach is used to construct an approximate linear system model for complex flows. The linear quadratic Gaussian (LQG) control synthesis is then used to design optimal controllers for the identified linear model. A system-identification-LQG approach is applied to control a separated boundary layer flow on a flat plate. The controller design based on the identified linear model is shown to reduce the time-averaged separation bubble size. SUBJECT TERMSFlow control, separation control, detached-eddy simulation, systems-theory approach, system identification. The objectives of this project are twofold: to develop a detached-eddy simulation (DES) technique for turbulent flows past an airfoil at a high angle of attack, and to explore new control strategies for the separated flow, utilizing modern control theories.The ability to control flows to achieve a desired effect is a matter of tremendous consequence in many applications. Not surprisingly, there has been enormous interest in controlling flows to achieve such effects for well over a century. Traditional flow control approaches have been based primarily on the control designers' physical insight into the relevant flow physics together with some simple trial and error. While such approaches have been successful and will continue to play a significant role, the incorporation of model-based control theory into fluid mechanics presents new opportunities for many open problems in fluid mechanics.The systems theory approach to flow control, in which modern control theories are utilized in designing optimal control inputs, is a new promising approach to flow control in general and turbulence control in particular. While it has been demonstrated that the systems theory approach is indeed a viable and promising approach to controlling simple flows (e.g., turbulent channel flows and boundary layers), extending this appro...

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“…They employed a proportional feedback controller to suppress the convection and investigated how the gain of the proportional controller affects the linear stability of the Rayleigh-Bénard convection. Other related problems are control of shear-driven channel or boundary layer flows [7][8][9]. In this work, they simplified the governing equations to facilitate the implementation of the optimal control schemes.…”

Section: Introductionmentioning

confidence: 99%