Concerning the curvature of an airfoil (shape) I am wondering about the reasons for the shape of a turbine blade airfoil, see here
Do you know the reason for this shape? Usually, very large curvatures like this are to extract high lift from LOW speed environments. But the conditions inside a turbine is the most strenuous for any object, and the speeds are certainly not low (right?)
 A: Turbine blades can actually have a very complex shape, which changes dramatically from the root to the tip. That diagram is a little misleading as it only shows one cross section.
The shape at the root is indeed at a high angle of attack, and is quite broad - partly as it needs the strength to cope with the large forces at work in a rapidly spinning blade. Towards the tip the angle reduces dramatically, and the cross section thins out a lot as speed increases.

From blog.nikonmetrology.com
A: Thanks to Rory for the great picture.
The difference between a turbine blade and a wing is that.


*

*A wing has to impart no more momentum per second to the fluid than the aircraft weighs, or a small multiple of that, in either a positive or negative direction, so it is not changing the direction of flow by much of an angle. During landing, the effective curvature of the wing is increased by using flaps and slats, so the same momentum per second can be gotten at a slower speed.

*A turbine blade needs to impart maximum momentum per second to the fluid, turning it through as large an angle as possible. What's more, it has to do it at a range of input velocities, from cruising speed down to near zero.
