[conspire] Tacoma Narrows (was: Janet Jackson vs. Laptop Hard Drives)

[Nick Moffitt]

On 19Sep2022 12:38am (-0700), Deirdre Saoirse Moen wrote:
> Has to do with resonant frequencies. But given that the song is in the (quite common) key of E (aka default tuning for a guitar), why *just that song*?
> 
> Adam has some answers, with some cool history like 19th century orchestra arms races.
> 
> https://www.youtube.com/watch?v=-y3RGeaxksY

I am disappointed that he brought up the Tacoma Narrows bridge as an analogy.  It's long been understood that resonant harmonics were *not* the reason for the buckling and swaying, but rather the natural oscillations of a wind blowing one side up until it was no longer at an angle to be blown up, at which point it went back down again.

The excellent engineering disaster podcast (with slides), Well There's Your Problem, always had a running gag that "Our next episode will be the Tacoma Narrows bridge disaster".  They never did that episode, until they finally got the donations together to do a live show and that had to be the topic: https://youtu.be/O3Qv7-DxA6c

It's an hour and 20 minutes of a live show, for a podcast that is very chatty at the best of times, but the relevant bit is here:

	https://youtu.be/O3Qv7-DxA6c?t=1915

It's worth a watch, but the key question is: how could this be, unless the wind were blowing in bursts of once per second?