Minni sub is at the bottom of the river, the fail safe died on me and it never surfaced. Two trial runs no problem, the third was a disaster. I know where it's at, it's lodged in the mud at the bottom. Just got to figure out a way to get it out.
(don't have diving certs, though for the cost of that thing, it would be worth it to get them)
As for formula one cars, I can't speak for them. As for the shuttle I recall that being true.
Your right about the many orders of harmonics, the harmonics of a wave is a component the signal frequency that is an multiple of the fundamental frequency for which all will be the same period at the signal frequency. That takes you into Fourier's in which the periodic function degrades into the sum of oscillating functions. (sines/cosines)
This is where welding/metals bridged into sound and vibration when fourier was working up the heat equation in plate.
to understand what they are after for this will take a pile of reading.
In a nutshell (not perfectly correct but down and dirty summarized) Fourier was trying to model a complicated heat source as a superposition.
http://www.kettering.edu/~drussell/Demos/superposition/superposition.htmlIn the process of this, a multitude of discoveries were made, the applicable ones relating to vibration analysis which opens up several worm cans. In short, modeling the interactions real time, and modifying the various solidification phases in that the sub harmonics vibrates them into a relieved state real time.
I don't purport to understand it completely and will therefore insert that caveat, but I do understand direct results. I've seen it work. I'll leave it to the scientist in the group to explain it in better detail.
It's taken me several years of study to get to the point I am at, and still I am lacking. You will understand why when you start delving into the various intricacies of the problem. (hilbert space, Euclidean space, Sturm-liouville theory, partial differential equations, Paley wiener theory etc etc) I simply don't have time to get into like I need to for a full understanding and still work. For me I have enough to understand that it can in fact be done, that real time as welded inspections is a distinct possibility awaiting the proper computational speed and programming, and that there is more to this than is generally realized in the industry as a whole.
Regards,
Gerald