Prandtl Lifting Theory for Finite Wings — Lesson 3

This lesson covers the in-depth understanding of Prandtl's Lifting Line Theory. It starts with the discussion of the trailing vortex sheet and the concept of a continuous distribution of gamma along the lifting line. The lesson further explains the induced angle of attack, the geometric angle of attack, and how they relate to the lifting line theory. It also discusses the concept of down motion and its integration along the entire lifting line. The lesson concludes with the application of Prandtl's Lifting Line Theory to elliptic lift distribution and a general lift distribution. For instance, it explains how the lift and induced drag of a wing can be calculated using this theory.

Video Highlights

01:21 - Explanation of the down motion and its integral along the lifting line.
07:32 - Discussion on the lift per unit span and the Kutta Jaakowski's theorem.
11:14 - Explanation of the Prandtl's lifting line theory.
14:18 - Discussion on the lift and induced drag coefficients.
17:48 - Explanation of the elliptic lift distribution.
28:06 - Discussion on the general lift distribution.

Key Takeaways

- Prandtl's Lifting Line Theory proposes a continuous distribution of gamma along the lifting line.
- The induced angle of attack and the geometric angle of attack are key concepts in this theory.
- The down motion along the entire lifting line can be calculated by integration.
- The theory can be applied to calculate the lift and induced drag of a wing.
- The theory can be used for both elliptic lift distribution and a general lift distribution.