Chapter 9 - 3D Flow

Question 1

Looking from behind which way do wing tip vortices rotate on the left?

Answer 1

Clockwise

Question 2

Looking from behind which way do wing tip vortices rotate on the right?

Answer 2

Anti- Clockwise

Question 3

tip vortex reduces if Wing aspect ratio, Aircraft speed and Amount of lift generated do what?

Answer 3

Wing Aspect ratio increases
Aircraft speed increase
Amount of life being generated decreases

Question 4

What creates a vortex

Answer 4

High pressure from under the wing coming round and having no where else to go

Question 5

Which x2 factors affect vortices intensity the most

Answer 5

The Px differential

The velocity the wing is travelling at. fast = less vortices created

Question 6

Downwash is created by vortices doing what

Answer 6

Each vortex rotates sharply downwards behind the trailing edge because of the airs viscosity this causes downward component of air to leave the trailing edge

Question 7

What other component is created by Vortices

Answer 7

Drag

Question 8

Pan wise flow goes from

Answer 8

root to tip under the wing

tip to root over the wing

Question 9

How are trailing edge vortices created

Answer 9

When x2 airflows (one H and one L) traveling in slightly different directions meet and cause a vortices

Question 10

Key point vortices give a velocity to downward air leaving the TE

Answer 10

Yes key for EAF

Question 11

In 3D flow what happens to down wash compared to 2D

Answer 11

becomes greater than the upwash

Question 12

Greatest downwash happens at the on a rectangle wing?

Answer 12

Tip of the wing

Question 13

The main difference between 2D and 3D flow is the EAF which is created by downwash and effects our?

Answer 13

wing aero dynamic forces

Question 14

The induced AOA is

Answer 14

The angle between the EAF and RAF

Question 15

Because the vector perpendicular to the EAF is rewards this creates?

Answer 15

induced drag

Question 16

The angle of attack using 3D flow is

Answer 16

Angle between the RAF and the longitudinal axis

Question 17

The induced AOA is larger when

Answer 17

Flying at a lower TAS

Or the vortices are larger due to to higher AOA or higher camber

Question 18

What is effective AOA

Answer 18

The angle between EAF and the chord line

Question 19

AOA is the sum of

Answer 19

Induced and Effective

Question 20

Small vortices = what effective AOA

Answer 20

shallow EAF which means large effective AOA which means small induced drag

Question 21

On rectangular wing how does the EAF change from root to tip

Answer 21

Root has a small angle for EAF - therefore large effective AOA and is produce most life per square area.

Tip has a large angle for the EAF - therefore small effective AOA and large induced AOA = induced drag