Velocity Measurement Using Particle Image Velocimetry- Cont'd — Lesson 2

This lesson covers the detailed aspects of Particle Image Velocimetry (PIV) and its role in modern aerodynamics. It delves into the requirements and challenges of PIV, including the need for high spatial and temporal resolution, and the necessity for adequate experimental data for validation. The lesson also discusses the importance of tracer particles and light scattering in PIV, and the use of lasers in low and high-speed PIV applications. For instance, it explains how Neodymium Yttrium Aluminum Garnet (Nd:YAG) lasers are used in low-speed PIV applications, while Neodymium Yttrium Lithium Fluoride (Nd:YLF) lasers are used in high-speed PIV applications.

Video Highlights

01:18 - Explanation of how PIV can be applied to different kinds of flow situations.
05:26 - Discussion on the challenges of PIV system in investigating air flows in wind tunnels.
11:50 - Explanation of the Stokes law for spherical particles and the concept of relaxation time.
20:49 - Explanation of the principles of light scattering, including Mie scattering and Rayleigh scattering.

Key Takeaways

- Particle Image Velocimetry (PIV) is a crucial tool in studying complex flow phenomena in aerodynamics.
- PIV requires high spatial and temporal resolution and adequate experimental data for validation.
- Tracer particles play a significant role in PIV, and their choice can significantly impact the results.
- Light scattering, including Mie and Rayleigh scattering, is a critical aspect of PIV.
- Lasers, specifically Nd:YAG and Nd:YLF, are commonly used in PIV for low and high-speed applications respectively.