Velocity Measurement Using Particle Image Velocimetry — Lesson 1

This lesson covers the concept of Particle Image Velocimetry (PIV), a flow visualization technique used to measure velocities and related properties in fluids. The lesson explains how PIV works, its advantages over other methods, and its limitations. It discusses the process of using tracer particles to measure flow field velocity, the importance of homogeneous distribution of these particles, and the role of illumination in capturing accurate images. The lesson also touches on the use of lasers, optics, and computer techniques in PIV, and the potential for improving temporal resolution with high-speed lasers and cameras. An example of using PIV in a wind tunnel setup is also provided for better understanding.

Video Highlights

01:12 - Introduction to the concept of flow field velocity measurement.
04:51 - Discussion on the different types of particle image velocimetry setups.
09:32 - Explanation of the importance of homogeneous distribution of tracer particles.
17:26 - Explanation of the limitations in temporal resolution in particle image velocimetry.

Key Takeaways

- Particle Image Velocimetry (PIV) is a non-intrusive method used to measure velocities in fluids.
- PIV uses tracer particles to measure flow field velocity, requiring a homogeneous distribution of these particles for accurate results.
- The illumination duration and time delay between illumination pulses are crucial for capturing accurate images.
- PIV offers high spatial resolution but has comparatively low frame rates, which can be improved with high-speed lasers and cameras.
- PIV requires optical access to the test section of the wind tunnel for both the delivery of the light sheet and recording of images.