Post on 18-Jan-2016
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Slide 1 Den Haag September 2007
POD used as a filtering methodExample: Poorly seeded Helium Jet
Raw ImagesSubtract the Mean image
Calculated Instantaneous
velocity vectors
Decompose the flow, and preserve the highest energy levels (Here
upper 10%)
Slide 2 Den Haag September 2007
POD as filtering• Holes in gappy dataset
• Poorly seeded TR measurements often have that
VectorsImage POD Projection (90% of energy)
Slide 3 Den Haag September 2007
POD as filtering• Example – a jet where the surrounding air has not been seeded
Slide 4 Den Haag September 2007
EndoscopesSetup for 3D PIV
Two different endoscopes:
-Normal end
-45 slanted end
Slide 5 Den Haag September 2007
Endoscopic light sheet optics
Slide 6 Den Haag September 2007
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ResultsRotor - Position 1in-plane velocity
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Rotor - Position 1out-of--plane velocity
Rotor-Position 1Instantaneous Vortivcity
More details about the measurements in a transonic test turbine can be found in: Lang et al., "Stereoscopic particle image velocimetry in a transonic turbine stage", Experiments in Fluids 32, 2002, pp 700-709
Slide 7 Den Haag September 2007
• Slow, low-turbulentwater flow
• 60 µm polyamide particles
• 20W AR-Ion laser w. scanning mirror
• NanoSense camera
• Frame rate ~100 Hz
• Measuring distance 3.7m(1.2 m in water)
• Measuring area820 x 1000 mm
I.e. almost 1 m2 !!!
Large area TR-PIV
Slide 8 Den Haag September 2007
Understanding tip vortices in detailswith PIV measurements in water
x/b=6.80.2 nm
K. & C. Huenecke, Airbus
x/b=30.00.9 nm
x/b=63.02.0 nm
1962 CTA measurements in open air,waiting for the fly-by of the aircraft
Wingtip vortices, then and now
Slide 9 Den Haag September 2007
Laser housing on vertical traverse
1 - 6 m down
10 m laserumbilical
Power supplyon platformTowed
aircraftmodel
Cross section of HSVA tank
Submerged PIV for large towing tank
Slide 10 Den Haag September 2007
Vector Field Vorticity
Click on the picture
Slide 11 Den Haag September 2007
Trajectory of the Vortex Core
y-z
Slide 12 Den Haag September 2007
Vector Field and Velocity Magnitude
Click on the picture
Slide 13 Den Haag September 2007
Thank you!