Ben Falconer [email protected] Supervisors: Peter Bryanston-Cross, Brenda Timmerman.
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Transcript of Ben Falconer [email protected] Supervisors: Peter Bryanston-Cross, Brenda Timmerman.
![Page 1: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman.](https://reader038.fdocuments.in/reader038/viewer/2022110209/56649e495503460f94b3ca6f/html5/thumbnails/1.jpg)
Systems for
High VelocityParticle Image Velocimetry
Supervisors: Peter Bryanston-Cross, Brenda Timmerman
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Credit: AEF
• Quieter Aircraft– 96EPNdB for night takeoff/landing– Noise produced by turbulence close to engine
Why?
Credit: Steve Allen
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• Turbulence produces noise– Far field noise produced close to engine– Affected by area under wing– Dependent on velocities
Far Field Noise
𝑢𝑟𝑚𝑠=√ 1𝑁 ∑𝑖=1
𝑁
(𝑢𝑖❑−𝑢)2
Turbulence strength
Number of readings
Velocity fluctuation
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Particle Image Velocimetry?
Velocimetry (ˌvɛləˈsɪmɪtrɪ) n.
The measurement of the velocity of fluids
Abbreviated to PIV
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• Seed flow• Illuminate• Take images• Cross correlate
How PIV Works
Credit: LaVision
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• 2 Cameras• Resolves 3
components• Angle to focal
plane– Optimum θ=45°
Stereo PIV
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• Focus on non-perpendicular planes• Lens held at angle
Scheimpflug Principle
![Page 8: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman.](https://reader038.fdocuments.in/reader038/viewer/2022110209/56649e495503460f94b3ca6f/html5/thumbnails/8.jpg)
• One of the largest anechoic chambers in The World– 27m x 26m
x 16m– Large scale
tests• 1:10
Noise Test Facility
Credit: QinetiQ
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• No one enters during tests– Control centre 200m away
• Expensive– £10,000/hour
• Compressor– 400m/s
Noise Test Facility
Credit: QinetiQ
![Page 10: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman.](https://reader038.fdocuments.in/reader038/viewer/2022110209/56649e495503460f94b3ca6f/html5/thumbnails/10.jpg)
• Flow moving 400m/s• Can’t get close
– But particles only 0.3µm
• Remote operation• Must be fast• Full range of
distances
In Practice
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• 4m x 2.6m x 4.7m• Around flightstream• 2.7m optical standoff• Mounted on 2D
traverse• Bi-directional
Full Range Rig
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• Enables viewing 2 targets– For parallel planes– Preserves stereo
Mirrored Scheimpflug
![Page 13: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman.](https://reader038.fdocuments.in/reader038/viewer/2022110209/56649e495503460f94b3ca6f/html5/thumbnails/13.jpg)
• 4m x 2.6m x 4.7m• Around flightstream• 2.7m optical standoff• Mounted on 2D
traverse• Bi-directional
Full Range Rig
![Page 14: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman.](https://reader038.fdocuments.in/reader038/viewer/2022110209/56649e495503460f94b3ca6f/html5/thumbnails/14.jpg)
• Cameras moved– View under wing
• Lasers moved– Avoids wing
• Upstream• Stereo view
Wing Rig
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• Hostile conditions– Vibrations kill hard drives
• Remote access• Data throughput
– Images are acquired at 60MB/s per camera– Theoretical max 125MB/s on gigabit Ethernet– 80MB/s with overheads
Computer System
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• Control computer– Synchronises cameras and lasers– Accurate to nanosecond scale
• Solid statecomputers– Close to cameras– Not affected by
vibrations– Low storage capacity
Rig Computers
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• Storage servers– Dedicated gigabit Ethernet each– ~3.5TB per server– Away from vibrations
Control Room
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• 2 Control computers– 1 or 2 person operation– Calculate 880,000 run parameters– Organise 40TB of resulting data
Control Room
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• Velocity maps–Time averaged
Results
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• Turbulent kinetic energy– Indicates variation in velocity
• Closest measurement to actual acoustics
Results
𝐸𝑘=12
((𝑢1′ )2+(𝑢2′ )2+(𝑢3′ )
2)
Velocity fluctuation
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Questions?
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• Correlation between axes
• Can be extended to rotation
What’s Next?
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• Out of plane rotation
What’s Next?
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Computer System
![Page 25: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman.](https://reader038.fdocuments.in/reader038/viewer/2022110209/56649e495503460f94b3ca6f/html5/thumbnails/25.jpg)
Computer System
• Additions to base system– Mirrors– Focusing– CCTV– Remote
power
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• 880,000 measurements– 1100 measurements per position– 20 positions per condition– 40 conditions
• 40TB of data– 3 Cameras– 16MB per image– 880,000 measurements
Configurations