On the Flow Physics of Effectively Controlled Open Cavity Flows

On the Flow Physics of Effectively Controlled
Open Cavity Flows
Lawrence Ukeiley# and Louis Cattafesta&
T. Lusk, K. Hughes, Y. Zhang, H. Takahashi, F. Liu,
M. Palaviccini, M. Oyarzun, J. Griffin
#University
of Florida
&Florida State University
Introduction
Cavity flows (weapons bays, wheel wells, etc…) display intense
aeroacoustic phenomena which after many years of study still have several
open questions especially as one tries to control them
Rossiter Modes (tonal)
Surface Pressure
Characteristics
152
SPL [dB] with P
ref
= 20Pa
150
148
146
144
142
140
138
Point of actuation
0
500
1000
1500
2000
Freqency [Hz]
Broadband
2500
3000
3500
Objectives
Goal: Develop a better understanding of the flow field effects from
successful applications of flow control for the reduction of surface
pressure fluctuations in open cavity flows.
• Advance applications of closed loop flow control algorithms

Improve time dependent actuators that can be used for adaptive flow
control in high speed applications
• Detailed flow measurements of cavity flows with reduced surface
pressure fluctuations
• Understand the effects of actuator flow interaction

Actuator orientation and spacing
 Effects of steady vs. time dependent actuation
Time Dependent Actuation
Objective & Methods
To understand the effects of various active flow control
methodologies to reduce flow-induced
cavity oscillation
Control methodologies using ZNMF actuator array :
 Open-Loop (OL)
 Sinusoidal wave

Closed-Loop (CL)
 Downhill Simplex (DS)
 ARMARKOV disturbance rejection
 Generalized predictive control (GPC)

Three-dimensional Spanwise Control of the ZNMF actuator
Flow visualization to understand flow physics
 Schlieren Visualization & Particle Image Velocimetry (PIV)
Open-Loop Sinusoidal Control
(Mach 0.3 and 0.4)
f = 1100 Hz, Vpp = 50 V
OASPL  10 log10 ( Prms Q)
% reduction in rms pressure fluctuations
→ ∆% Prms
24.7 %
16.7 %
Mach 0.4
Mach 0.3
-25
-25
TE Baseline
TE Control-Open Loop
-30
/Q [dB]
-35
-40
rms
-45
-50
P
P
rms
/Q [dB]
-35
-40
-45
-50
-55
-55
-60
-60
-65
0
TE Baseline
TE Control-Open Loop
-30
1000
2000
Freq. [Hz]
3000
4000
-65
0
1000
2000
Freq. [Hz]
•Multiple Rossiter modes are reduced
•Broadband pressure fluctuations are also reduced
3000
4000
Schlieren Visualization
Mach 0.4 (Open Loop)
Single-Shot Image
Mach 0.4 Controlled
M = 0.4, Controlled, Single-shot image
0
0
100
100
y, pixel
y, pixel
Mach 0.4 Baseline
0.3, Single-shot image
M = 0.4,
200
300
200
300
0
100
200
300
400 500
x, pixel
600
700
800
0
100
200
300
400 500
x, pixel
600
700
800
700
800
Time-Averaged Image (100 frames)
Mach 0.4 Controlled
M = 0.4, Controlled, Averaged image
0
0
100
100
y, pixel
y, pixel
Mach 0.4 Baseline
M = 0.4, Baseline, Averaged image
200
300
0
200
300
100
200
300
400
500
600
700
800
0
100
200
300
400
500
600
Open-Loop Sinusoidal vs.
Downhill Simplex (Mach 0.3)
• Open-Loop
• f = 1100 Hz, Vpp = 50 V
• Downhill Simplex
• f = 1125 Hz, Vpp = 50 V
% reduction in rms pressure fluctuations
24.7 %
26.0 %
-25
-25
TE Baseline
TE Control-Open Loop
-30
/Q [dB]
-35
-40
rms
-45
-50
P
P
rms
/Q [dB]
-35
-40
-45
-50
-55
-55
-60
-60
-65
0
TE Baseline
TE Control-DS(Sinusoidal)
-30
1000
2000
Freq. [Hz]
3000
4000
-65
0
1000
2000
Freq. [Hz]
•Multiple Rossiter modes are reduced
•Broadband pressure fluctuations are also reduced
3000
4000
Comparisons of OL & CL
Control Method
Open-Loop
DS – Sinusoid
DS – AM
DS – BM
ARMARKOV*
GPC*
Mach 0.3 (50 Vp-p)
Overall power
% Prms
reduction [dB] reduction [%]
-2.5
24.7
-2.6
26.0
-1.3
13.9
-1.9
19.5
-1.6
16.8
-1.6
16.7
Mach 0.4 (75 Vp-p)
Overall power
% Prms
reduction [dB] reduction [%]
-2.4
24.4
-3.1
30.3
-1.1
11.5
-2.2
22.4
-
* Input voltage: 100 Vp-p
•Multiple Rossiter modes are reduced
•Broadband pressure fluctuations are also reduced
•OL and DS-Sinusoidal show good performance
3-D Spanwise Control of the
Spanwise Wave
Synthetic Jet Actuator
Excitation
To generate three-dimensional
spanwise perturbation input from
the synthetic jet actuator
 each actuator cell has a different
phase angle
Cavity
Actuator orifices
z
Main flow direction
V(t) = Asin(βz - ωt)
Cavity Leading Edge
30
Flow pattern: from Brès&Colonius (2008) and Faure et al. (2007)
30
20
Prms Reduction [%]
Prms Reduction [%]
25
15
10
5
0
0
=0
Spanwise
0.5
1
1.5
Normalized Spanwise Wavelength:  /D
2
Comparison of Prms reduction [%] for OL sinusoidal control
(β = 0) and spanwise OL sinusoidal control (M=0.3, fc = 1100Hz).
20
Vpp = 10V
Vpp = 20V
Vpp = 30V
Vpp = 40V
Vpp = 50V
10
0
-10
0
500
1000
1500
Carrier frequency, Hz
2000
Prms reduction [%] as function of the frequency
and Vpp (M=0.3, λ/D=1).
Summary
Closed loop control with time dependent
actuation can be fruitful yet there is need for
improvements to expand the free stream range
which it can be applied successfully.

Increased actuator authority

Better actuator flow coupling
Therefore we are using steady blowing to asses actuator
configurations
Steady Blowing Active Control
• Subsonic
• Supersonic (M=1.4)
Subsonic Steady Blowing
Nine slot geometries for steady blowing jet actuators were investigated
for their control performance on cavity flow oscillations.
• Free-stream Mach number from 0.3 to 0.7
• Spanwise and Streamwise slot geometries examined
• 1 to 9 slots investigated always covering the center of the
tunnel where pressure sensors were located.
Spanwise Configurations
Streamwise Configurations
Spanwise wavelengths of disturbances ranging
from /D=0.6 through /D=0.2
Aft Wall Overall Pressure
Reductions (Subsonic)
15
Mach 0.4
60
10
50
reduciton
0
-5
%P
rms
-10
-15
-20
Stream-wise 3
Stream-wise 5
Stream-wise 7
Stream-wise 9
-25
0.2
0.3
Span-wise 1
Span-wise 3
Span-wise 5
Span-wise 7
Span-wise 9
20
10
0
-30
0
0.4
0.05
0.1
0.15
C
0.2
0.25
0.3
0.35
C
45
50
40
35
40
reduciton
30
25
20
rms
15
10
%P
reduciton
0.1
30
-20
rms
-30
0
40
-10
%P
%P
rms
reduciton
5
5
Stream-wise 3
Stream-wise 5
Stream-wise 7
Stream-wise 9
0
Mach 0.6
-5
-10
0
0.1
0.2
0.3
C
0.4
0.5
30
20
10
Span-wise 1
Span-wise 3
Span-wise 5
Span-wise 7
Span-wise 9
0
-10
0.6
-20
0
0.05
0.1
0.15
C
0.2
0.25
0.3
0.35
Aft-Wall Spectra
span-wise 3-slot
Ma=0.3,C=0.19554
Ma=0.4,C=0.16703
120
110
2000
3000
4000
5000
140
135
130
125
120
115
6000
TE Wall--baseline
TE Wall-control on
145
1000
Frequency [Hz]
2000
3000
5000
6000
145
140
135
130
125
120
1000
2000
165
TE Wall--baseline
TE Wall-control on
160
150
140
130
1000
2000
3000
4000
Frequency [Hz]
5000
6000
TE wall--baseline
TE wall--control on
160
155
150
145
140
135
130
3000
4000
Frequency [Hz]
Ma=0.7, C=0.17133
Ma=0.6,C=0.23566
170
120
4000
TE Wall--baseline
TE Wall-control on
150
Frequency [Hz]
SPL [dB]@20 Pa
1000
155
SPL [dB]@20 Pa
130
SPL [dB]@20 Pa
TE Wall--baseline
TE Wall-control on
140
100
Ma=0.5,C=0.19355
150
SPL [dB]@20 Pa
SPL [dB]@20 Pa
150
1000
2000
3000
4000
Frequency [Hz]
5000
6000
5000
6000
Instantaneous Schlieren
Mach 0.6
span-wise 3-slot
Baseline
stream-wise 3-slot
Average Schlieren
Mach 0.6
span-wise 3-slot
Baseline
stream-wise 3-slot
Mean Velocity (Mach 1.4)
Downstream of slot shear layer growth rates are decreased
but the point of maximum mean shear is raised
Downstream of gap shear layer growth rates are increased
however the 5 slot case levels off near the center of the cavity
Mach 0.7
Steady Blowing Active Control
• Subsonic
• Supersonic (M=1.4)
Slot Blowing Configurations
Streamwise Configurations
Spanwise Configurations
All dimensions
in mm
/D=2 and /D=1
Cavity model construction
L=76.2 mm (3”)
L/D=6
W/D=6
/D=2 and /D=1
Kulite Locations
Aft Wall Overall Pressure
Reductions (Subsonic)
Spanwise Configurations
Streamwise Configurations
Aft-Wall Spectra
3-slot
5-slot
5-slot
Streamwise Configurations
Spanwise Configurations
1-slot
6-slot
10-slot
Flow Visualization
Spanwise Slots
Baseline
1-slot
3-slot
5-slot
Flow Visualization
Streamwise Slots
Baseline
5-slot
6-slot
10-slot
Flow Visualization
Streamwise Slots
5-slot
10-slot
Mean Velocity (y-z plane)
x/D = 1
x/D = 2
x/D = 4
x/D = 5
2
2
2
2
1
1
1
1
1
Baseline
y/D
0.8
0.6
0.4
0
0
0
0
-1
-1
-1
-1
0.2
0
-2
-1
0
1
2
2
-2
-1
0
1
2
2
-2
-1
0
1
2
2
-0.2
-2
-1
0
1
2
2
1
3-Slot
y/D
0.8
1
1
1
1
0
0
0
0
0.6
0.4
0.2
0
-1
-1
-2
-1
0
1
2
-1
-2
-1
0
1
2
-1
-2
-1
0
1
2
-0.2
-2
2
2
2
2
1
1
1
1
-1
0
1
2
1
5-Slot
y/D
0.8
0.6
0.4
0
0
0
0
-1
-1
-1
-1
0.2
0
-2
-1
0
z/D
1
2
-2
-1
0
z/D
1
2
-2
-1
0
z/D
1
PIV results presented last year, Lusk et al Exp. In Fluids (2012)
2
-0.2
-2
-1
0
z/D
1
2
Supersonic Baseline Flow
<u(y,z)>- U(y)
X/D=4.0
X/D=2.0
Summary
&
Research Direction
• Summary

Feedback control with spanwise arrays of ZNMF actuators can reduce both broadband
and tonal surface pressure fluctuations
 Spanwise aligned slots tend to be more effective than streamwise aligned slots
 In subsonic flow, 3 and 5 slot configurations were most effective (/D=0.6 and
/D=0.3)
 In supersonic flow, a 5 slot configuration was most effective (/D=1)
• Currently Examining

PIV measurements with effective slot orientation in subsonic flows
 Spanwise distribution of aft wall pressure transducers
 Baseflow perturbations in subsonic cases
• Direction

Push closed loop control to supersonic free stream conditions
 Look to stability analysis for further optimization of slot configurations
 Use numerical simulations to perform global stability analysis to highlight preferred
wavenumbers
 Synchronous flow and surface pressure measurements, Schlieren , PIV
• Publications

Journal



Lusk, T., Cattafesta, L., and Ukeiley, L., (2012) “Leading Edge Slot Blowing on an Open Cavity in
Supersonic Flow,” Vol. 53, No. 1, pp. 187-199.
Takahashi, H., Liu, F., Palaviccini%, M., Oyarzun%, M., Griffin%, J., Ukeiley, L. and Cattafesta,L.,
“Experimental Study of Adaptive Control of High-Speed Flow-Induced Cavity Oscillations,” (2011) Journal
of Fluid Science and Technology, Vol. 5, No. 5, pp. 701-716.
Conference



Liu, F., Oyarzun, M., Takahashi, H., Griffin, J., Palaviccini, M., Ukeiley, L., and Cattafesta, L., (2011)
“Active Control of Open Cavities,” AIAA Paper 2011-1221, AIAA Aerospace Sciences Meeting.
Lusk*, T., Dudley*, J., Ukeiley, L., and Cattafesta, L., (2011) “Flow Field Effects of Control on Supersonic
Open Cavities,” AIAA Paper 2011-0039, AIAA Aerospace Sciences Meeting.
H. Takahashi, F. Liu, M. Palaviccini, M. Oyarzun, L. Ukeiley, and L. Cattafesta, "Experimental Study of
Adaptive Control of High-Speed Flow-Induced Cavity Oscillations", Seventh International Conference on
Flow Dynamics, Sendai, Japan, Tohoku University Global COE Program
• Student Supports

T. Lusk (MS), K. Hughes (PhD), Y. Zhang (PhD)
• Post Doc Support

H. Takahashi