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amorriison May 15, 2003 14:10

A different view
 
Consider the "visuals" of the following:

1/ "Standard" wind tunnel wing c/w streamlines. - At low AoA the air is leaving the trailing edge at an angle of -say- 15 degrees below horizontal

2/ A helicopter rotor in the horizontal plane. - At low blade AoA the airflow is STRAIGHT DOWN

So why the difference?

In 1/ the air is moving over the stationary wing

In 2/ the wing is "cutting" through the stationary air

Why in "all" textbooks is option 1/ chosen? Maybe this was the "standard" and "only" option before CFD visuals.

Why not use CFD to promote the visuals of option 2 which in my opinion is the more "truthful" option since in the end lift is the reaction force to air being "forced" vertically downward by the "wing".

amorriison May 27, 2003 15:11

Re: A different view
 
OP again.

Support for this "view" can be found in this excellent paper BUT no CFD support to produce option 2/ views.

http://www.aa.washington.edu/faculty.../Lift_AAPT.pdf


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