On Sun, 8 Feb 2015 19:10:02 +0000 (UTC), "Danny D."
wrote:

John Larkin wrote, on Sun, 08 Feb 2015 09:39:53 -0800:

Don't all those trees sway (asynchronously!) in the wind?

You could occasionally get the equivalent of a rogue wave, a big spike
of acceleration.

I'm not sure how they sway in the wind, but, we decoupled the 75-foot
long bridge from the middle trees after that last storm, and we're
hoping to see the bridge still there after the one that is raging as
we type.
https://c4.staticflickr.com/8/7394/1...b70b7c5d_c.jpg

Yeah, we're getting some wild gusts today in the Alemany Gap, a break
in the coast hills between the ocean and the bay, our own local wind
tunnel.

https://dl.dropboxusercontent.com/u/...MtSanBruno.JPG


One thing we noticed is that, in the wind, the bridge actually *rises*
a few inches, like what happens with an airplane wing or a sailboat sail.

Since the bottom is dirtier, with respect to laminar flow, we suspect
the air flows faster over the top than over the bottom:
https://c1.staticflickr.com/9/8647/1...7c0b7fba_b.jpg

The whole bridge is roughly the size of an airplane wing:
https://c1.staticflickr.com/9/8642/1...972b0444_c.jpg

Yikes. Suspension bridges have all sorts of aerodynamic issues.
Galloping Gertie and all that.

https://www.youtube.com/watch?v=j-zczJXSxnw


--

John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com