Tuesday, December 15, 2009

Continuing apace, upscaling granular interactions

One of the things sedimentologists try to do is visualize how individual grains behave. This is important for things like sediment transport and deposition - it even plays an important role in things like quicksand. In some cases, it's helpful to scale a system down so that it may be observed in a lab room, under manageable timescales. I've been working on scaling things up to look at how individual grains interact with each other. A few thousand fluorescent BBs and a blacklight help bring out the details look pretty interesting with a long-exposure photograph.


  1. Very interesting (and beautiful). Reminds me of elegant scaling up experiments on insect wings in which mineral oil was used to simulate air and keep Reynolds number similitude: e.g. http://plus.maths.org/issue17/news/bumble/index.html

  2. Cool pic! Where do you get a few thousand fluorescent BBs from?

  3. Aydin,
    They're "airsoft" gun bb's - they sell them in packs of several thousand. They come in many colors, including a few nicely fluorescent ones. I think they may be a better choice than metal BBs for some photography needs, too (well, perhaps a different color than blaze orange).