Pressure measurement using 3 holes / probes I — Lesson 4

This lesson covers the principles and applications of pressure measurement using probes, specifically focusing on multi-hole probes. It delves into the operational principles of different instruments used to measure pressure, highlighting the advantages of using probes. The lesson further discusses the use of 3-hole and 4-hole probes in measuring several flow parameters like total pressure, static pressure, flow velocity, and flow angles. It also explains the limitations of 3-hole probes and how 4-hole probes overcome these limitations. For instance, the lesson illustrates how an extra hole in a 4-hole probe enables the measurement of pitch characteristics in a flow field, which is not possible with a 3-hole probe.

Video Highlights

01:39 - Advantages of using probes in fluid mechanics
10:31 - Limitations of 3-hole probes
27:37 - Introduction to 4-hole probes and their advantages
39:56 - Detailed explanation of the construction and operation of 4-hole probes

Key Takeaways

- Multi-hole probes are commonly used in fluid mechanics for their simplicity, low cost, and easy maintenance.
- 3-hole probes are suitable for measuring flow parameters in largely two-dimensional fields. However, they cannot measure pitch characteristics of the flow.
- 4-hole probes, with an extra hole located at the tip, can measure pitch characteristics, making them suitable for three-dimensional flow fields.
- The use of 4-hole probes allows for simultaneous measurement of static pressure, dynamic pressure, flow velocity, and flow angles.