In the Lord of the Rings fandom there’s a persistent debate whether balrogs, or Durin’s Bane specifically, have wings. The text in Fellowship is ambiguous whether what it is describing are literal wings or something else wing-like.
In the Lord of the Rings fandom there’s a persistent debate whether balrogs, or Durin’s Bane specifically, have wings. The text in Fellowship is ambiguous whether what it is describing are literal wings or something else wing-like.
Exactly how planes fly. I studied a bit of fluid dynamics in grad school and my professor was adamant that any explanation is incomplete without discussion of boundary layers.
In short the explanation was a couple things. The first is how ping pong balls generate lift with translation and rotation (or vorticity). Its basically the shape of the wing that helps with vorticity (this is what generates the pressure difference above and below the wing). The second is that you need laminar flow over the wing for vorticity to take place, and this is achieved when a thin layer of turbulent air surrounds it, the boundary layer. It moves the stagnation points towards the back (encouraging laminar flow) and reducing drag.
The same process is the reason golf balls have dimples on them, to help form a turbulent boundary layer, moving the stagnation pounts, reducing drag and allowing the ball to go further.
“Tripping the boundary layer” can be achieved by increasing speed on the runway, a strong head wind, rough spots on the wing, or how you might see windsurfers pump their sail, or someone pumping on a hydrofoil board in the water.