Thermal Anemometry and Hot wire Anemometer II — Lesson 4

This lesson covers the principles and applications of thermal anemometry in the field of fluid mechanics. It delves into the concept of flow measurements, focusing on the use of thermal anemometry to measure point velocity. The lesson explains the two modes of operation for thermal anemometry: constant current mode and constant temperature mode. It also discusses the design modifications needed to measure different velocity components in turbulent flows. For instance, the lesson highlights the use of two wires at right angles to each other for measuring two velocity components. The lesson also addresses the limitations and complications of using thermal anemometry, such as temperature and humidity fluctuations, thermal interactions between the wire and solid surfaces, and turbulent intensity.

Video Highlights

00:28 - Introduction to thermal anemometry and its use in flow measurements
20:32 - Explanation of constant current mode and constant temperature mode
33:53 - Discussion on design modifications for measuring different velocity components
42:57 - Limitations and complications of thermal anemometry

Key Takeaways

- Thermal anemometry is a crucial tool in fluid mechanics for measuring point velocity.
- The instrument can operate in two modes: constant current mode and constant temperature mode.
- Design modifications, such as using two wires at right angles, can allow the measurement of different velocity components.
- Despite its advantages, thermal anemometry has limitations, including sensitivity to temperature and humidity fluctuations, thermal interactions with solid surfaces, and turbulent intensity.
- Despite these challenges, extensive research and understanding of the physics of thermal anemometry have made it a reliable and popular instrument for flow measurements.