reynolds number
jan,
Perhaps it would be easier to think of it as a property of the fluid
(in this case - air) - not the wing...
The air is moving past the wing(!) and will stratify (or separate into
layers) moving at different speeds.
Read these arrows as a vectors - direction and length = velocity
----------------------------------------- Free stream velocity
------------------------------------
------------------------------ boundary layers move faster
--------------------------
---------------------
-----------------
------------- boundary layers move slower
--------- closer to surface
---
========================================= surface
In special cases, air in the the boundary layer can even move
in the OPPOSITE direction!
----------------------------------------- Free stream velocity
------------------------------------
------------------------------ boundary layers move faster
-------------------------- farther from surface
---------------------
-----------------
------------- boundary layers move slower
--------- closer to surface
-----
- here, the flow has reversed
---
========================================= surface
Note: the Re of the layers could be different due to differences in
velocity.
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