Figure 6

Displacement thickness and displacement area in a deformed tube. Illustration of the displacement thickness δ*, the momentum thickness θ and the total displacement thickness δ** in a deformed cross-section. The related areas are the displacement area A _δ*(dark grey), the momentum area A _θ (light grey) and the total displacement area A _δ**= A _δ*+ A _θ (light + dark grey) respectively.