Flow Through Converging Diverging Nozzle Under Different Back Pressure; Flow Past an Airfoil Over a Range of Freestream Mach Number — Lesson 7

This lesson covers the principles of flow through converging and diverging nozzles, and the impact of different back pressures on isentropic and non-isentropic cases. It also discusses the flow past an airfoil or a wedge over a range of free stream Mach numbers, from moderately compressible subsonic flow to highly compressible hypersonic flows. The lesson further explains the formation of shock waves, the concept of shock wave boundary layer interaction, and the effects of these phenomena on aerodynamic performance and drag. It concludes with a discussion on the utility of supercritical airfoils in managing these issues.

Video Highlights

01:11 - Discussion on the concept of accelerating isentropic flow through a supersonic nozzle.
05:01 - Explanation of the concept of flow past an airfoil over a range of free stream mach numbers.
15:01 - Discussion on the concept of transonic flow.
22:55 - Explanation of the concept of shockwave boundary layer interaction.
27:27 - Discussion on the impact of increasing free stream mach number on flow past an airfoil.

Key Takeaways

- The area-velocity relation in subsonic and supersonic conditions is crucial in understanding the behavior of flow through converging-diverging nozzles.
- The formation of shock waves and their interaction with the boundary layer significantly impact the aerodynamic performance and drag of an airfoil.
- Supercritical airfoils are preferred at supersonic speeds due to their ability to suppress flow separations and associated complexities, resulting in reduced drag.
- The Mach number at any location in the duct is a function of the ratio of local duct area to the sonic throat area.
- The concept of shock wave boundary layer interaction is important in understanding the behavior of flow past an airfoil at high Mach numbers.