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