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Week 10: Imaging Flow Around a Radio
Controlled Race Car
The purpose of this lab is to:
• learn about PIV techniques,
• make instantaneous full field velocity
measurements of flow around a model race car
• Continue your CFD simulations.
Particle Image Velocimetry
• Particle Image Velocimetry (PIV) is a
quantitative flow visualization technique
which allows for full field quantitative
measurement of fluid velocities.
• Other techniques are single point methods:
• hot-wire anemometry (HWA)
• laser-Doppler anemometry (LDA)
• pitot probes
PIV Configuration
• a light source (usually a double-pulse laser),
• light-sheet optics (beam combining optics, beam
delivery, and light-sheet formation optics),
• tracer particles
P IV o p tic a l c o n fig u ra tio n
• camera (imaging lens and recording media).
http://www.youtube.com/watch?v=BcueRJml30c
In PIV, the fluid to be studied is seeded with small, neutrally
buoyant particles upstream of the zone of interest. The zone is
illuminated by a light sheet which is pulsed at two known
intervals. The initial pulse freezes images of the first position
of the seed particles onto a camera; the second pulse records
images at the particles final position.(see Figure 2) The two
camera images show the initial and final positions of the
particle as it moves through the flow field.
The images are then processed using a Correlation Technique
to find the velocity vector map of the flow field as shown
below.
Today
• PIV DEMO and CFD Work
• Finalize Memo CFD (due Friday)