Feedback Control of a Circular Cylinder Wake in Experiment and Simulation (Invited)

Siegel, Stefan; Cohen, Kelly; McLaughlin, Tom

doi:10.2514/6.2003-3569

Cited by 57 publications

(33 citation statements)

References 13 publications

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“…In Koopmann's experiment (1967), this amplitude was at 10% peak displacement of the cylinder. Siegel et al (2003a) show that for a circular cylinder, at Reynolds number of 100, a closed-loop controller operating within the "lock-in region" achieves a drag reduction of close to 90% of the vortex-induced drag, and lowers the unsteady lift force by the same amount.…”

Section: Closed Loop Control Methodologymentioning

confidence: 96%

“…This simple control approach was later modified by Siegel et al (2003a) when applying it to a high resolution CFD simulation. An adaptive gain strategy, based on the estimation of the "mean-flow" mode incorporated to tune the phase of a Proportionalwww.intechopen.com Differential (PD) controller was used (Siegel et al, 2003a). The closed loop feedback simulations explore the effect of both fixed phase and variable phase feedback on the wake.…”

Section: B Development and Analysis Of A Control Lawmentioning

confidence: 99%

“…Furthermore, the controller acts upon information provided by a set of sensors. During the past years, the closed-loop flow control program research effort at the United States Air Force Academy (USAFA) focused on developing a suite of low-dimensional flow control tools based on the low Reynolds numbers (Re ~ 100-300) cylinder wake benchmark , Cohen et al, 2005, Siegel et al, 2003a Several computations and experiments were also performed for the cylinder wake at high Reynolds numbers (Re=20000) (Aradag, 2009, Aradag et al, 2010 Energy is introduced into the flow via actuators and the flow field in the wake of a cylinder may be influenced using several different forcing techniques with the wake response being similar for different types of forcing (Gillies, 1998) The following forcing methods have been employed: external acoustic excitation of the wake, longitudinal, lateral or rotational vibration of the cylinder, and alternate blowing and suction at the separation points (Gillies, 1998). Work at USAFA has shown that the Dielectric Barrier Discharge (DBD) plasma actuator (Munska and McLaughlin, 2005) is an effective means of forcing at higher frequencies without mechanical movement.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Methodology Based on Experimental Investigation of a DBD-Plasma Actuated Cylinder Wake for Flow Control

Cohen¹,

Aradağ²,

Siegel³

et al. 2012

Low Reynolds Number Aerodynamics and Transition

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Section: Closed Loop Control Methodologymentioning

confidence: 96%

Section: B Development and Analysis Of A Control Lawmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Methodology Based on Experimental Investigation of a DBD-Plasma Actuated Cylinder Wake for Flow Control

Cohen¹,

Aradağ²,

Siegel³

et al. 2012

Low Reynolds Number Aerodynamics and Transition

Self Cite

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“…The first mode, Ψ(1,1), represents the mean natural flow. The second mode, Ψ(1,2), is a linear combination of the mean flows during the natural and forced states and is related to the 'shift" mode [6,21,22]; the third and the fourth modes, Ψ(1,3) and Ψ (1,4), describe the vortex shedding behind the cylinder and higher modes are responsible for the transient regime between the natural and the control cases. Temporal coefficients for these first six Ψ-modes, calculated by projecting TPOD mode into the spatial Ψ-mode frame of reference, are shown in Figure 7, right plot.…”

Section: A Tpod Modesmentioning

confidence: 99%

A Temporal Proper Orthogonal Decomposition (TPOD) Method for Closed-Loop Flow Control

Gordeyev

Thomas

2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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Motivated by closed-loop flow control applications, a new formulation of the proper orthogonal decomposition (POD) is presented which is capable of characterizing not only the controlled and natural states of a given flow but also the transient behavior between these states. This approach, which is termed temporal POD (TPOD) extracts the optimum frameof-reference and the temporal information regarding the dynamics of the system in the presence of the flow control. The TPOD concept is developed in this paper and demonstrated experimentally in an application involving a circular cylinder in cross flow at Re D = 5,000 with active plasma flow control. The resulting model is shown to properly capture the correct dynamics of the first TPOD mode, including the natural, forced and transient regimes. I. Motivation and ObjectivesONVENTIONAL proper orthogonal decomposition (POD)-based modeling extracts an optimal complete set of dominant (in the energy sense) spatial modes, with a minimum number of modes to represent a particular flow state [1][2][3] . These modes are usually projected onto the Navier-Stokes (N-S) equations to obtain a low-dimensional system of ODE equations to describe the temporal evolution of the modes 4,5 . This approach is shown to give satisfactory results, if the flow does not deviate much from a given state, such as the natural evolution of a shear layer or jet, for instance. But when the flow is actively manipulated using some form of flow control, the set of POD modes extracted from the natural flow state typically does a very poor job describing the forced or controlled flow state. From a topological point of view, this can be explained as shown in Figure 1: for the natural state the dynamical system (the flow) occupies a particular finite region in phase space. POD extracts a set of eigenvectors (modes) and provides a low-dimensional frame of reference to describe the system evolution within this region. When the flow control is activated, the system is forced to travel and to occupy a different finite region in the phase space. So, the set of POD modes derived to describe the system evolution in one region with as few eigenvectors as possible becomes quite non-optimal for another region, and, although the set of POD modes is still complete, it results in dramatic increase in the number of POD modes needed to provide a proper frame of reference to describe the forced system.To address this issue, several modifications of the basic POD approach have been proposed to solve this problem. For periodic flows, the double POD or DPOD approach 6, 7 provides a set of POD modes calculated within each period, and performs a second POD-optimization among POD

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“…16 Flow visualization of the cylinder wake at Re ¼ 120, forced at the natural shedding frequency with an amplitude of 30 per cent of the cylinder diameter [12 -14] Fig. 17 Flow geometry around a circular cylinder including sensor placement and control concept [12][13][14] computed using the Navier -Stokes solver Cobalt, and the POD analysis was done with MatLab. Figure 17 shows the feedback loop after information from MatLab, which is used to oscillate the cylinder normal to the free stream flow to excite or dissipate the vortex wake.…”

Section: Argus Missile Configurationmentioning

confidence: 99%

Continuing evolution of aerodynamic concept development using collaborative numerical and experimental evaluations

Cummings

Morton

2006

Proceedings of the Institution of Mechanical Engineers, Part G:

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Traditionally, computational predictions and experimental evaluations of aerodynamic concepts have been conducted separately, with little collaboration other than post priori comparisons of results. This has led to distrust and even antagonism between the computational and the experimental communities. These difficulties probably began when early computational fluid dynamic practitioners boasted that wind tunnels would become sec ondary in aerodynamic concept development within a few short years, a prediction that has not come true. On the contrary, it is believed that a great deal of synergy can be cultivated when computational and experimental evaluations are conducted in an integrative fashion. A variety of projects where this has been done will be reviewed, including a pitching Unmanned Combat Air Vehicle, a delta wing with periodic suction and blowing for aerodynamic control, a missile with drag brakes that caused excessive unsteady flow, a C-130 aircraft configured for airdrop, and closed-loop flow control. Further evolution of the numerical/experimental collaboration will be discussed showing results from the flow control research where the dividing line between numerical predictions and experimental evaluations is becoming blurred. Suggestions for future directions in collaboration will also be made.

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Feedback Control of a Circular Cylinder Wake in Experiment and Simulation (Invited)

Cited by 57 publications

References 13 publications

A Methodology Based on Experimental Investigation of a DBD-Plasma Actuated Cylinder Wake for Flow Control

A Methodology Based on Experimental Investigation of a DBD-Plasma Actuated Cylinder Wake for Flow Control

A Temporal Proper Orthogonal Decomposition (TPOD) Method for Closed-Loop Flow Control

Continuing evolution of aerodynamic concept development using collaborative numerical and experimental evaluations

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