Two photos, one question

[asakiyume]

Little Springtime works at the media lab at her university. They have a 3D printer, which, from next semester (... I think?) will be available to students to use. She tested it out and made a hedgehog.



Yesterday and today have been cold, with magnificent if somewhat ominous high winds, but the day before yesterday was warm and melty. Melted snow was coursing down the road. Or rather, it was lapping down the road.

Why does it go down the road in ripples like this? (See the smiles, one after the other? Those are the ripples I'm talking about.) Why not one smooth sheet of water?

Comments

[docdad2.livejournal.com]

The water flowing speed is limited by the lower interface and upper free flowing. It builds up a 'Wave" much like you wee at beaches.
Nice use of a 3D printer.

[asakiyume.livejournal.com]

so the friction on the interface causes the water to build up? And that's what makes the wave form?

[docdad2.livejournal.com]

the water exposed to air flows faster than the water against the pavement based on the depth of the water sheet. The wave builds up as a result of the friction between the two flow rates. The wave's weight then speeds up its movement and the speed is maintained by the height of the "Wave".

[asakiyume.livejournal.com]

**thank you**

[greylistening.livejournal.com]

Learning this has made me very happy. Thank you! :)

[genarti]

This is so cool. It never occurred to me that wave physics would apply so visibly to such shallow streams of water. Thank you!