Continuous Closed Circuit Supersonic Wind Tunnel; Similarity Analysis in Experimental Aerodynamics — Lesson 5

This lesson covers the estimation of ideal power required to run a continuous closed circuit supersonic wind tunnel and the concept of dimensional analysis. It delves into the principles of the Buckingham Pi theorem, which is a crucial tool in engineering and experimental aerodynamics. The lesson also explains how to identify similarity parameters for use in aerodynamics experiments at both low and high speeds. For instance, it explains how to reduce the number of independent variables from five to two, simplifying the problem dramatically and saving a significant amount of effort and time.

Video Highlights

01:56 - Discussion on the entropy removal per unit mass and the total entropy removal.
05:39 - Explanation of how dimensional analysis can be used to determine the variation of forces and moments on an aerodynamic body.
10:30 - Explanation of how to define the Pi products in dimensional analysis.
17:44 - Discussion on the significance of Reynolds number and Mach number in aerodynamics.
22:15 - Discussion on the additional considerations for performing a dimensional analysis of compressible flows.

Key Takeaways

- The ideal power required to run a continuous closed circuit supersonic wind tunnel can be estimated using certain assumptions and equations.
- The Buckingham Pi theorem is a crucial tool in engineering and experimental aerodynamics, helping to simplify complex problems.
- Dimensional analysis can be used to identify similarity parameters for use in aerodynamics experiments at both low and high speeds.
- The lesson also highlights the importance of considering additional aspects such as the ratio of specific heat at constant pressure to that at constant volume, the ratio of wall temperature to free stream temperature, and the Prandtl number when performing a dimensional analysis of compressible flows.