Chapter 9: 3 Dimensional Flow

Question 1

Spanwise flow

Where is it strongest

Answer 1

Spanwise flow -> Flow from root to tip. Creates vortices. Strong at tip, weak at root.

Question 2

Vortex

Answer 2

Inertia of air mass
i.e. fast speed or low taper ratio -> less time for vortex
Differential pressure
i.e. high Cl, high AC mass,

Question 3

Downwash

Answer 3

Large vortex = large downwash

Rectangular wing, large vortex at wingtip

Question 4

AoA Definitions

Answer 4

2D - chord and RAF
3D - longitudinal axis and RAF
Induced - RAF and EAF (effective AF)
Effective - chord and EAF

2D = Induced + effective