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Characterization of Laser Energy Deposition for Aerodynamic Flow Control
Tierra RollerAerospace Engineering, University of Arizona
Mentor: Dr. Jesse LittleAssistant Professor, Department of Aerospace and Mechanical Engineering,
University of Arizona
Arizona Space Grant ConsortiumApril 18, 2015Phoenix, AZ
2
Acknowledgements
• Research Group Members:• Clark Pederson• Liliana Saldaña• David Akins• Robyn Dawson
• Space Grant Administrators and Mentors• Air Force Office of Scientific Research
3
Flow Control• Flow control:
improves the aerodynamic performance of a surface
• Active: not a permanent alteration of the surface
• Energy deposition: adding energy to the flow
Baseline
Control
Images from Ely and Little, 2013
4
0 5 10 15 20 25 301.8
2
2.2
2.4
2.6
2.8
3
3.2
Wind Tunnel, Laser turned on ~ 5 s
Time (s)
Ve
loc
ity
(m
/s)
Wind Tunnel Test
Trailing edge
High velocity
Low velocity
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Effect of the Laser
100 200 300 400 500 600 700 800 900 10000.080.09
0.10.110.120.130.140.150.160.170.18
Time of Laser Exposure Effect
Time Laser Has Run (s)
% In
crea
se in
Vel
ocity
6
Schlieren Imaging
• Bending of light through density gradients
• Propagating shock wave associated with the rapid heating of the surface
Shock wave
Low density region
7
Schlieren Imaging Setup
Laser – Plate Interaction
8
Quantitative Results
Shock wave
9
Analysis
• Similar curves• Need better tunnel data
100 200 300 400 500 600 700 800 900 10000.08
0.09
0.1
0.11
0.12
0.13
0.14
0.15
0.16
0.17
0.18
Time of Laser Exposure Effect
Time Laser Has Run (s)%
Inc
rea
se
in V
elo
cit
y
10
Next Steps
• Get a fuller, more accurate curve for velocity change• Run the tunnel test keeping the velocity
measurement in the same location
• Repeat the process with various metals• Steel and copper• Improve wind tunnel testing
11
Thank you
12
Ablation Damage
Permanent damage due to ablation
13
Schlieren Imaging
Image from John and Keith 2006