Active Control of Instabilities in Laminar Boundary Layers—Overview and Concept Validation

Ronald, D Joslin; Erlebacher, Gordon; Hussaini, M. Y.

doi:10.1115/1.2817785

Cited by 51 publications

(14 citation statements)

References 19 publications

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“…19 They showed that it was possible to delay accelerate transition by superposing disturbances out of in phase with the primary TS wave. Similar results were also reported by Danabasoglu et al 20 Finally, Joslin et al 21 performed a numerical experiment which served to unequivocally demonstrate the link between linear superposition and instability suppression. To ensure that linear superposition of individual instabilities was, in fact, responsible for the results found in previous experiments and computations, they carried out three simulations with i only the disturbance; ii only the control; and iii using both disturbance and control, which is the wave-cancellation case.…”

Section: The Wave-cancellation Conceptsupporting

confidence: 70%

“…From the wave-cancellation study of Joslin et al, 21 the relationship between amplitude of the actuator v a with resulting instabilty can be shown in Fig. 6.…”

Section: Resultsmentioning

confidence: 99%

“…As described by Joslin et al, 21;28 these discrete small-amplitude instabilities can be suppressed through wave cancellation WC using known information about the wave. Hence, the optimal control is known" for validation of the present DNS optimal control theory numerical approach in which the instability is to be suppressed without any a priori knowledge of said instability.…”

Section: Numerical Experimentsmentioning

confidence: 99%

See 2 more Smart Citations

Self-contained automated methodology for optimal flow control

Joslin¹,

Gunzburger²,

Nicolaides³

et al. 1997

AIAA Journal

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This paper describes a self-contained, automated methodology for active o w control which couples the time-dependent N a vier-Stokes system with an adjoint N a vier-Stokes system and optimality conditions from which optimal states, i.e., unsteady ow elds and controls e.g., actuators, may be determined. The problem of boundary layer instability suppression through wave cancellation is used as the initial validation case to test the methodology. Here, the objective of control is to match the stress vector along a portion of the boundary to a given vector; instability suppression is achieved by c hoosing the given vector to be that of a steady base ow. Control is e ected through the injection or suction of uid through a single ori ce on the boundary. The results demonstrate that instability suppression can be achieved without any a priori knowledge of the disturbance, which is signi cant because other control techniques have required some knowledge of the ow unsteadiness such a s frequencies, instability t ype, etc. The present methodology has been extended to three dimensions and may potentially be applied to separation control, re-laminarization, and turbulence control applications using one to many sensors and actuators.

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Section: The Wave-cancellation Conceptsupporting

confidence: 70%

“…From the wave-cancellation study of Joslin et al, 21 the relationship between amplitude of the actuator v a with resulting instabilty can be shown in Fig. 6.…”

Section: Resultsmentioning

confidence: 99%

Section: Numerical Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

Self-contained automated methodology for optimal flow control

Joslin¹,

Gunzburger²,

Nicolaides³

et al. 1997

AIAA Journal

Self Cite

View full text Add to dashboard Cite

show abstract

“…Most of the results, however, report incomplete destruction of instability waves. Joslin et al (1994) explain that wave cancellation is very sensitive to the wave parameters and postulate that incomplete destruction reported in past studies was due to improper phase or amplitude properties of the cancelling wave.…”

Section: Introductionmentioning

confidence: 99%

“…A nice survey of past work is given in Joslin, Erlebacher & Hussaini (1994). The basic idea is that boundary layer instabilities appear as a combination of many sinusoidally growing waves of certain frequencies, phases, and amplitudes.…”

Section: Introductionmentioning

confidence: 99%

A systems theory approach to the feedback stabilization of infinitesimal and finite-amplitude disturbances in plane Poiseuille flow

1997

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A systems theory framework is presented for the linear stabilization of two-dimensional laminar plane Poiseuille flow. The governing linearized Navier-Stokes equations are converted to control-theoretic models using a numerical discretization scheme. Fluid system poles, which are closely related to Orr-Sommerfeld eigenvalues, and fluid system zeros are computed using the control-theoretic models. It is shown that the location of system zeros, in addition to the well-studied system eigenvalues, are important in linear stability control. The location of system zeros determines the effect of feedback control on both stable and unstable eigenvalues. In addition, system zeros can be used to determine sensor locations that lead to simple feedback control schemes. Feedback controllers are designed that make a new fluid-actuator-sensorcontroller system linearly stable. Feedback control is shown to be robust to a wide range of Reynolds numbers. The systems theory concepts of modal controllability and observability are used to show that feedback control can lead to short periods of highamplitude transients that are unseen at the output. These transients may invalidate the linear model, stimulate nonlinear effects, and/or form a path of 'bypass' transition in a controlled system. Numerical simulations are presented to validate the stabilization of both single-wavenumber and multiple-wavenumber instabilities. Finally, it is shown that a controller designed upon linear theory also has a strong stabilizing effect on two-dimensional finite-amplitude disturbances. As a result, secondary instabilities due to infinitesimal three-dimensional disturbances in the presence of a finite-amplitude two-dimensional disturbance cease to exist.

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A method for optimal control in boundary‐layer flow

Dumiţrache

2007

Proc Appl Math and Mech

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A methodology for active flow control which couples unsteady flow fields and controls is described. Active-control methods are used to maintain laminar flow in a region in which the natural instabilities lead to turbulent flow. The simplest form of control which might achieve this objective is the wave-cancellation approach. The case of boundary layer instability suppression is considered as the initial validation and test case. Control is effected through the injection or suction of fluid through a single orifice on the boundary. The optimal control theory provides an approach which does not require a priori knowledge of the flow.

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Active Control of Instabilities in Laminar Boundary Layers—Overview and Concept Validation

Cited by 51 publications

References 19 publications

Self-contained automated methodology for optimal flow control

Self-contained automated methodology for optimal flow control

A systems theory approach to the feedback stabilization of infinitesimal and finite-amplitude disturbances in plane Poiseuille flow

A method for optimal control in boundary‐layer flow

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