4 ms·
As mentioned by others, the photography technique looks like (and apparently is a software enabled variant of) Schlieren photography. This(1) is a neat example
by wolfram74 8y ago
As mentioned by others, the photography technique looks like (and apparently is a software enabled variant of) Schlieren photography. This(1) is a neat example of an old school Schlieren set up capturing shockwave formation during whip cracks. I highly recommend it.
(1) https://www.youtube.com/watch?v=AnaASTBn_K4 https://www.youtube.com/watch?v=AnaASTBn_K4
- nate_meurer 8y agoVery cool. They didn't mention this in the video, but I immediately see one groundbreaking new phenomenon that they uncovered: at the exact moment the end of the whip goes supersonic, it is being accelerated by something other than the tension of the rope. It looks as though it's accelerated by the shockwaves, of which there appear to be two -- one on each side of the whip end, with a vacuum in between. It's as clear as day in the video. The rope in front of it clearly goes lax, and the whip end even changes direction to align with the shock wave propagation.
- nate_meurer 8y agoI thought about this and watched the video again, and I've changed my mind just a bit. It looks like, instead of being accelerated, the whip end is experiencing reduced drag in the vacuum between the two shock waves. We can see that it travels right behind the first shockwave, not lagging at all, and this is exactly what you would expect if it is both the source of the shockwave and the beneficiary of the vacuum behind it.