Measurement of Pressure Using Mechanical Instruments — Lesson 3

This lesson covers the measurement of pressure using mechanical instruments, focusing on the use of a pitot static tube. The lesson delves into the structure of the pitot static tube, explaining how it measures pressure through several tappings in the same radial plane. It also discusses the importance of the tube's alignment with the incoming flow to minimize disturbance. The lesson further explores the use of the pitot static tube in a converging diverging passage, explaining how the tube can be traversed to measure pressure at different points. The lesson also touches on the use of manometers and boundary layer probes in pressure measurement.

Video Highlights

01:18 - Explanation of how the pitot static tube measures pressure.
05:00 - Explanation of how the pitot static tube is used in a converging diverging passage.
10:26 - Discussion on the importance of pressure ports in aerodynamics experiments.
14:24 - Introduction to manometers and their role in pressure measurements.
19:52 - Explanation of how the sensitivity of a manometer can be enhanced by changing its orientation.
24:38 - Discussion on the use of boundary layer probes for measuring velocity profiles.

Key Takeaways

- The pitot static tube is a slender tube aligned parallel to the incoming flow to minimize disturbance. It measures pressure through several tappings in the same radial plane.
- The tube can be used in a converging diverging passage, where it can be traversed to measure pressure at different points.
- Manometers are used in pressure measurement, with their sensitivity increasing when they are inclined.
- Boundary layer probes are used for boundary layer velocity profile measurement. They are designed to reach very close to the wall to measure very low pressures accurately.
- The placement, orientation, and design of the probe are crucial in obtaining accurate pressure readings.