dome stuctures ~ wind resistance

[Terry Tyler]

i was driving home the other day, and i saw these dome houses...which are fairly common around the area...and it got me to thinking...do these structures have a higher tolerance to straight-line winds/tornadoes then conventional structures?

tell me what you think...

some appear to be manufactured from steel...while others seem to be a clothy material or even fiberglass material...that being said, i have never actually touched one so i dont know...i wonder how these would be classified on a DI...

 

[Doug Lee]

Just speculation using some old info...

Years ago, OU put out a 3 volume set of coffe-table sized books on Thunderstorm Dynamics and Morphology. I remember looking through those and finding that a cylinder has a wind resistance coefficient of .8. I assume that a flat wall has a coefficient of 1, because it offers the maximum resitence to wind flow.

A cylinder has curvature around one axis. A dome has curvature around two axes, so now I suppose that a dome has a wind resistence coefficient of .8 x .8 = .64. In practical terms, the same damage, done by a wind at x speed, to a structure with flat walls would require a wind speed at the inverse of .64 (1.5625) times x. In other words to have the same effect as a 100 mph wind on a regular house, the wind would have to blow at 156 mph.

The only concern I see is with straight winds. The 2D vertical profile of a dome resembles a aircraft wing somewhat. If the dome is not anchored securely enough and the winds are strong enough, the winds could lift the dome and do damage that way. However, the probabilities of this is very small.

But as I said, this is all speculation on my part. It would take someone with an engineering background to fully answer this question. I am a drafter, but I do mostly mechanical drawings. Tim Marshall is the only one on this forum I am aware of who has an engineering background. There may be others, but I am not aware of who they are.

 

[Terry Tyler]

wow, that is an amazing explanation douglas...thank you...

 

[Glenn Rivers]

Domes and Wind

Actually, if the drag coefficient was .64 the wind pressure would be 64 % of that experienced by a flat wall. But since wind pressure increases as the square of wind speed the the wind would only have to increase by a factor of (1/.64)^.5 = (1.5625)^.5 = 1.25. Therefore a wind of 125 mph would at a drag coefficient of .64 would create the same wind pressure as a 100 mph wind at a drag coefficient of 1.

 

[Gaetan Cormier]

While watching one of Reeds video on Youtube, I came accross a video response from this dude and he talks about those dome housing has being the best solution and that they last for a lifetime... and more

Here's the video link:
http://www.youtube.com/watch?v=huJFO5c5q9o&watch_response

Warning! You might be temped to laugh at this guy appearance... but listen to what he has to say... real cool!