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Closed-Loop Control of SeparatedClosed-Loop Control of Separated Turbulent Flows with Dynamically
Articulating Geometries presented atpresented at
GDR <<Flow Separation Control>> Meeting06-07 December 201006-07 December 2010
Futuroscope, Poitiers, France byby
R. Wallace, P. Shea, and M. GlauserV Thi kk d H C l
Syracuse University
Cle S ie e CV. Thirunavukkarasu and H. CarlsonRyan Schmit
Clear Science Corp.
Air Force Research Laboratory
F T t f A tiFocus on Turrets for Aero-optics ApplicationsApplications
AIAA June 2010 YAW\AIAA June 2010Updated_dec.ppt
APS 2010 Turret SARL\APS 2010.ppt
Shea_APS_2010.pptx
All material has been cleared for Public Presentation
Closed-loop Flow Control for an Articulating Turret with Two Degrees ofArticulating Turret with Two Degrees of
Freedom: Pitch and Yaw
R Wallace P Shea and M Glauser Syracuse UniversityR. Wallace, P. Shea, and M. GlauserV. Thirunavukkarasu and H. Carlson Clear Science Corp.
The Issuee ssueThe performance of lasers is degraded
th li ht th h t b l tas the light passes through turbulent regions such as wakes and shear layers
Wh f i t tWhy of interestOn board aircraft lasers housed within a 3D turret
• Aero-opticsK Gilbert 1982
Boeing website
– K. Gilbert, 1982• Aero-optic effects
– E. Jumper et. al. 2001• Adaptive optic control
– A. J. Smits and J. P. Dussauge, 2006• Strong velocity and density fluctuation correlationg y y
Previous Active Control Aero-Optic WorkPrevious Active Control Aero Optic Work
• B. Vukasinovic et al., 2009– Open Loop Control using
synthetic jets
Vukasinovic et al 2009Vukasinovic et al., 2009
• S. Gordeyev et al., 20052005
• Passive control
Gordeyev et. al., 2005
Previous Work: Closed Loop Control
Simple Proportional Closed Loop Control
Andino et. al 2008, Andino et. al 2009, Wallace et. al 2009, Andino et al, (to appear, AIAA Journal, January 2011)
Simple Proportional Closed Loop Control( )( )00
12sin)()( ttftaKtu
M
nn −⎥
⎦
⎤⎢⎣
⎡−= ∑
=
πClosed Loop Control input:
Flow driven towards homogeneity and integral time scales significantly reduced
Control Input: Synthetic Jets
scales significantly reduced
Motivation for Suction I ti ti b D t h d Edd Si l ti h dInvestigation by Detached Eddy Simulation showed suction gives an improvement in reducing the Optical Path Difference RMS and controlling the separationPath Difference RMS and controlling the separation bubble over the aperture
Reduction of OPDrms with suctionVorticity for baseline and a constant suction
Work done by Clear Science Corporation supported by a Phase I SBIR
Previous WorkClosed Loop PitchingClosed Loop Pitching
Simple Proportional Feedback Controller
Feedback Sensor Velocity
Plane
[ ]rmspKtu −=)(Actuator InputU∞
Plane
Flow Control OnNo Flow Control
Closed Loop Pitching with Advance ControllerController
Development and Implementation of a Reduce Order Model
Dynamical Estimator with Kalman filter Multiple pressure sensors
Velocity data
Controller gains calculated using a Linear Quadratic Regulator
Key Advantage of the Dynamical Estimator ControllerAble to keep the flow attached with a higher efficiency
T. Vaithianathan, et. al, “Feedback Flow Control for a PitchingTurret (Part I)," AIAA Paper 2010-0360, 48th AIAA Aerospace Sciences M ti O l d FL 2010
For further details please see:Meeting, Orlando, FL, 2010.
R. D. Wallace, et. al, “Feedback Flow Control for a PitchingTurret (Part II)," AIAA Paper 2010-0361, 48th AIAA Aerospace Sciences Meeting, Orlando, FL, 2010.
Objective
• Reduce the velocity fluctuations in the wake over the aperture of a dynamically azimuthal rotating turret using unsteady g g ysuction flow control
Active Flow Control– Active Flow Control• Open Loop
Cl d l t l• Closed loop control
Due to the strong velocity and density fluctuationsDue to the strong velocity and density fluctuations correlation, the strategy for reducing velocity fluctuations can be applied to reducing density fluctuationsfluctuations
Test Conditions• Facility
– Syracuse University y ysubsonic wind tunnel
• TurretTurret– Hemisphere with flat aperture– AR = 1.3– Quarter ScaleQ
• ActuationS ti l t– Suction slots
• Around the aperture• Double row
Suction Slots
• Flow Conditions– Mach number ≈ 0.1
Re ≈ 500 000 Suction Slots– Re ≈ 500,000
Control Inputp• Suction Actuators
U t d V l– Unsteady Valves• On/Off operation only• Duty Cycle modulation for y y
control– Relation between Duty
Cycle and Velocity
Cµ
• Operation speed of 25 Hz
– Vacuum SourceV t d b t• Vacated by two vacuum pumps
• Pressure 0.9 psi Mean Coefficient of Momentum per slot– Coefficient of Momentum
• CµMAX = 1.68x10-4 per slot
Mean Coefficient of Momentum per slot
Measurement B.L.Pressure
Transducer
Pressure Transducer
• Dynamic Surface U
Transducer
y a c Su acePressure– Sampled at 10,000 Hz
U∞
Sampled at 10,000 Hz– 30 acoustic ICP pressure
transducers– Located on and around aperture
Pressure Transducer Locations ObservationPurpose
OnlyLocated on and around aperture
• Velocity– Stereo Particle Image VelocimetryStereo Particle Image Velocimetry– Centerline Plane
• Pressure and Velocity essu e a d e oc ySimultaneously SampledSampled
Dynamic Yawing: Velocity No ControlVelocity, No Control
Yawing Turret
Azimuthal Range0° to 10°
Static Elevation AngleStatic Elevation Angle115°
⎤⎡⎟⎞
⎜⎛ω
⎥⎦
⎤⎢⎣
⎡⎟⎠⎞
⎜⎝⎛−= tπωθ cos5100
Dynamic Yawing: Pressure, No Control
Fluctuating surface static pressure time series
Open Loop Control: VelocityVelocity
A constant signal of 50% duty cycle at 25 Hz
Baseline Flow
No Control
Open Loop Control
Open Loop Controller Results: Pressurep p
No Control Open loop ControlNo Control Open loop Control
Asymmetry in the flowDue to the strong asymmetry seen in theDue to the strong asymmetry seen in the flow the suction slots are divided into two halves.
Examine the use of multiple outputs
Closed Loop Flow Control• Measurement Estimator
– Pod/mLSE Estimator• J. Pinier et al., 2007
• Simple Proportional Feedback Controller is employed
⎥⎦
⎤⎢⎣
⎡−= ∑
=
M
nn taKtu
1)()(&⎦⎣ n 1
is the POD/mLSE expansion coefficients)(tan
Only the first mode is utilizedy
Block Diagram
Multiple Input Multiple Output Controller
Right Sensors and valves
Left Sensors and valves
Feedback signal time series
Sensors off aperture were used
Closed Loop Pitching Results: Velocity
No Control Closed Loop Flow Control
Closed Loop Controller Results: PressurePressure
No Control Closed loop ControlNo Control Closed-loop Control
Closed Loop Yawing Results
( ) ( ) ( )[ ] ( ) ( )[ ]{ }⎟⎟⎠
⎞⎜⎜⎝
⎛−+−≡ ∑
=
PIVN
iiiii
PIVrms xutxuxutxu
Ntu
1
222
211 ,,1Spacial Velocity rms
DCuu
BaselinermsControlrms −=ξController Efficiency
DC
Conclusion
– Dynamic yawing produces a strong asymmetry over the turretasymmetry over the turret
– Open Loop control reduced velocity fluctuationsfluctuations
– Closed loop control had the a greater d ti f l it fl t ti threduction of velocity fluctuations than open
loop control
Current Closed Loop Control InvestigationsConducted at the Subsonic Aerodynamic Research Laboratory wind tunnel at Wright-Patterson Air Force BasePatterson Air Force Base
Freestream Velocity = Mach 0.3
Reynolds Number of 2,000,000
The Test ModelControl input of suction
Similar geometry as SU tests
Capable of two degrees of freedom: Pitch and Yaw
SARL Tests Goals
ExperimentsExperiments•Baseline
•Open Loop ControlOpen Loop Control
•Closed Loop Control
Train and implement a reduced order model Dynamical Estimator with a Kalman filter intro a feedback closed loop controller
Compare the advantages of the various control schemes
SARL MeasurementsVelocity/surface pressureVelocity/surface pressure
OPD/Surface Pressure
A k l d tAcknowledgementsSupport through a Phase II SBIRSupport through a Phase II SBIR
James Myatt and Ryan Schmit project mangers
Questions???
CHARACTERIZATION OF A THREE-DIMENSIONAL
TURRET WAKE FOR ACTIVE FLOW CONTROLTURRET WAKE FOR ACTIVE FLOW CONTROL
PART II: EXPERIMENTAL STUDY
Patrick R. SheaChris J. Ruscher Ryan D. Wallace
Mark N Glauser John F Dannenhoffer IIIMark N. Glauser John F. Dannenhoffer, IIISyracuse University; Syracuse, NY
APS Division of Fluid Dynamics MeetingNovember, 2010
INTRODUCTIONI O U IO
Axisymmetric bluff bodies, typically referred to as turrets, are commonly used for optical housings on airborne platformscommonly used for optical housings on airborne platforms
A bl
cnet.com (Photo credit: Ed Turner, Boeing)
Aero‐optics problem— When density fluctuations are present, laser performance on moving
platforms is degraded as light passes through turbulent regions such as wakes and shear layers
PREVIOUS RESEARCHTurret flow fields
— LDA in the turret wakeA i e u e a eLeder et al. (2003)
— Force measurementsSnyder et al (2000) and Sluder et al (2008)Snyder et al. (2000) and Sluder et al. (2008)
— Surface flow visualizationGordeyev and Jumper (2010)
Aero‐optics active control research— Synthetic jet actuators
Gordeyev et al (2009) saw up to a 34% reduction in OPDRMSGordeyev et al. (2009) saw up to a 34% reduction in OPDRMSat Mach 0.3Andino et al. (2008) saw up to 19% reduction in surface pressure fluctuations on turret aperture at Mach 0.3p
— Dynamic suctionWallace et al. (2010) saw up to 48% reduction in mean RMS velocities above turret aperture at Mach 0.1velocities above turret aperture at Mach 0.1
EXPERIMENTAL TEST SETUPELow speed wind tunnel
Square test section of 0 61 m— Square test section of 0.61 m — Operated at 53 m/s
ReD ≈ 5 x 105
Turret— Axisymmetric geometry— Base diameter (D) of 0.152 m— Suction based active control— Fixed aperture angle of 120°Dynamic pressure sensors
— Sensitivity of 1500 mV/psiR l ti f 0 02 i— Resolution of 0.02 mpsi
— Resonant frequency ≥ 13 kHzDantec PIV system
Two 8 bit HiSense cameras U∞— Two 8‐bit, HiSense cameras— New Wave Gemini Nd:YAG laser— Double exposure/double frame
cross‐correlation
∞
TURRET CONFIGURATION
Active Flow Control— Suction around leading portion of aperture— cμ≈ 3.9 x 10‐4 per slot
U∞
PIV CONFIGURATION
Two‐dimensional data taken at center plane of turret ll l t th f tparallel to the free‐stream
— Composite data from 8 inspection regions500 snapshot ensemble average for each region
LaserLaser
Laser SheetInspectionRegion
yU
Laser Sheet g
x
U∞
Pressure SensorLocations
STREAMWISE VELOCITY CONTOURS
Baseline
OpenLoop Control
STREAMWISE VELOCITY CONTOURS
Baseline
OpenLoop Control
AUTO‐SPECTRAL DENSITY FUNCTION
UU∞
B d & Pi l (1980)Bendat & Piersol (1980)
AUTO‐SPECTRAL DENSITY FUNCTION
UU∞
AUTO‐SPECTRAL DENSITY FUNCTION
UU∞
CONCLUDING REMARKS
PIV and dynamic pressure measurements have been k i h k f i h d i h itaken in the wake of a turret with and without active
flow controlA ti e flo o t ol effe ti ely edu ed the i e of theActive flow control effectively reduced the size of the wakeDynamic pressure measurements indicated changes inDynamic pressure measurements indicated changes in the spectral characteristics of the wake flow field
— Changes in the spectral content were not consistent g pthroughout the wake
— Properly placed sensors can potentially be used for closed‐loop feedback flow controlloop, feedback flow control
ACKNOWLEDGEMENTS
AFOSR Grant with Clarkson UniversitySyracuse University Fellowship
Related upcoming talks from Syracuse University— Local Flow Control for Active Building Facades
Session EJ: Flow Control IIISession EJ: Flow Control III— A Closed‐loop Suction Flow Control Study over a Pitching Turret
Session EJ: Flow Control III