ben falconer [email protected] supervisors: peter bryanston-cross, brenda timmerman

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Systems for High Velocity Particle Image Velocimetry Ben Falconer [email protected] Supervisors: Peter Bryanston- Cross, Brenda Timmerman

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Page 1: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

Systems for

High VelocityParticle Image Velocimetry

Ben [email protected]

Supervisors: Peter Bryanston-Cross, Brenda Timmerman

Page 2: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

Credit: AEF

• Quieter Aircraft– 96EPNdB for night takeoff/landing– Noise produced by turbulence close to engine

Why?

Credit: Steve Allen

Page 3: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• 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

Page 4: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

Particle Image Velocimetry?

Velocimetry (ˌvɛləˈsɪmɪtrɪ) n.

The measurement of the velocity of fluids

Abbreviated to PIV

Page 5: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• Seed flow• Illuminate• Take images• Cross correlate

How PIV Works

Credit: LaVision

Page 6: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• 2 Cameras• Resolves 3

components• Angle to focal

plane– Optimum θ=45°

Stereo PIV

Page 7: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• 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

• One of the largest anechoic chambers in The World– 27m x 26m

x 16m– Large scale

tests• 1:10

Noise Test Facility

Credit: QinetiQ

Page 9: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• 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

• Flow moving 400m/s• Can’t get close

– But particles only 0.3µm

• Remote operation• Must be fast• Full range of

distances

In Practice

Page 11: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• 4m x 2.6m x 4.7m• Around flightstream• 2.7m optical standoff• Mounted on 2D

traverse• Bi-directional

Full Range Rig

Page 12: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• 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

• 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

• Cameras moved– View under wing

• Lasers moved– Avoids wing

• Upstream• Stereo view

Wing Rig

Page 15: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• 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

Page 16: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• Control computer– Synchronises cameras and lasers– Accurate to nanosecond scale

• Solid statecomputers– Close to cameras– Not affected by

vibrations– Low storage capacity

Rig Computers

Page 17: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• Storage servers– Dedicated gigabit Ethernet each– ~3.5TB per server– Away from vibrations

Control Room

Page 18: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• 2 Control computers– 1 or 2 person operation– Calculate 880,000 run parameters– Organise 40TB of resulting data

Control Room

Page 19: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• Velocity maps–Time averaged

Results

Page 20: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• Turbulent kinetic energy– Indicates variation in velocity

• Closest measurement to actual acoustics

Results

𝐸𝑘=12

((𝑢1′ )2+(𝑢2′ )2+(𝑢3′ )

2)

Velocity fluctuation

Page 21: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

Questions?

Page 22: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• Correlation between axes

• Can be extended to rotation

What’s Next?

Page 23: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• Out of plane rotation

What’s Next?

Page 24: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

Computer System

Page 25: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

Computer System

• Additions to base system– Mirrors– Focusing– CCTV– Remote

power

Page 26: Ben Falconer b.p.falconer@warwick.ac.uk Supervisors: Peter Bryanston-Cross, Brenda Timmerman

• 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