Double Diffusive Instablilty

If you can believe it, I've actually done an experiment and have video to prove it.

The double diffusive consisted of filling a 1 meter square by 1 cm deep tank with salty water such that the salinity concentration decreases linearly toward the top of the tank. A destabilizing vertical thermal gradient was then imposed from the back of the tank.

I was ultimately unsuccessful at my primary goal which was to observe the onset of layers due to the instability of the above configuration to double diffusion (see my paper above). The primary instability was due to lateral thermal gradients and therefore set a size scale for the layers. The experiment was, however helpful to understand layer interaction. A more thorough discussion can be found in the 1996 Proceedings of the Geophysical Fluid Dynamics Summer School at WHOI.

These are a list of images of the experiment we performed in 1996 at WHOI. They are all in GIF format.

  • He won the bet.
  • He's just stange.
  • Image1 A few minutes before figure 1 of my paper this still was taken.
  • Image3 Immediately before figure 1. This image has very good resolution.
  • Image4 Basically figure 1. The time stamp is blurred.
  • Image5 A few minutes after figure 1, not much more information.
  • Image7 This is taken a few minutes before figure 2, fair resolution.
  • Image9 Just after figure 2. This shows very pronounced layering, but the flow is not well visualized.
  • Image10 Just after figure 2. This is definitely the best of this series.
  • Image11 Much like Image 10, not as good.
  • Image12 Also like figure 10, just as good, but showing a large interfacial wave.
  • Instab1 Good image of onset of instability.
  • Plumes1 Not bad, showing plumes.
  • Plumes2 Same as above.

    The Guys

    Left to right, Steve, Bill, Francesco (behind Bill's head) me, Oliver (above), Neil (below), Barry (excited) and Paul (says "hi") in Jack Whitehead's Lab at WHOI. We are all overjoyed by a successful experiment on double diffusive instability.