Page 121 - Aeronautical Engineer Data Book

Basic aerodynamics 97

(a)
An effective rotational
velocity (vortex)
superimposed on the
parallel airstream
– – –
–
–
–
+
+
+ + +
Pressures equalize by flows
(b) around the tip
– – – – – – – –
Tip Midspan Tip
+ + + + + + + +

(c)

Finite airfoil Core of vortex
‘Horse-shoe’ vortex
persists downstream

Fig. 6.1 Flows around a finite 3-D airfoil

General airfoil section
L
Leading Camber line
edge Thickness
Trailing
D edge
a
Camber Chord
U l
Profile of an asymmetrical airfoil section
x
Centre line
Chord line t
c

Fig. 6.2 Airfoil sections: general layout