airfoils

[lucy_b14]

can anyone tell me the scientific reasons why airfoils are used to straighten airflow (e.g. turbulent flow from a fan or propeller). i know how they are used to produce lift, but cannot see how they straighten airflow.

thanx!
o:)

[Clausius2]

Has it something to do with this?:

http://www.physicsforums.com/showthread.php?t=52608

There two people answered you, but you seem not to be aware of that.

[lucy_b14]

yeh, its to do with my last post, but the replies don't seem to explain why an airfoil straightens airflow.

[enigma]

I get in the most descriptive manner I can think of, the answer is this:

If you put a flat plate in an airflow, it is not very condusive to changing direction of the flow. The flow on one side will bump into itself and become rough. On the other side, the sudden change in direction will cause the flow to seperate.

Airfoils however, sort of 'hug' a flow. They're designed to change the direction with the least amount of choppiness. Because of that, they'll switch the direction with much less turbulence.

Wow... that's handwavey. Did it make sense at all? :smile:

[lucy_b14]

thanks a lot! it does make sense