A sail is strung between the tops of two steel towers, each 610 meters tall, and separated by 3048 meters. A wind of 100 kph results in a horizonal force of 455,523,600 Newtons applied to the top of each tower. Guy wires are also attached to the top of each tower to balance this force, and fixed to the ground 610 meters from the base of each tower. The contributions of material weight to the static forces were ignored. I found the simple static relationship for buckling:
Minimum Area Moment of Inertia I = 2144 meters^4
Guy wires can be attached at several intermittent points along the tower for lateral bracing. This effectively reduces the height for buckling to shortest length. If we thereby subdivide the height by 4, then I is divided by 4^2 = 16.
I = 134 meters^4
Tubular steel construction gives us the following relationship for I:
t*d^3 = 341 meters^4
where,
t = tube wall thickness
d = tube diameter
For 15 cm thickness, we need a tube tower 13 meters (43 feet) in diameter.
.... which is admittedly pretty big. But not impossible.
Off Topic » in reply to re: All good points
But I just remembered that I started this thread... Ha! So I'll do a back-of-the-envelope calculation....
The whole thread (42 posts)
- Giant Wind Turbines
- re: Giant Wind Turbines
- Thought on caves.
- re: Is there anything wrong with this design.
- Stormblade
- The problem with wind turbines so far.
- people are already trying to build simmilar devices, called 'Solar Updraft Towers' I believe, in Australia (n/t)
- Make the tunnel parabolic in shape.
- re: Giant Wind Turbines
- re: Giant Wind Turbines
- Cost, time-to-build.