EDarelius&team – Adventures in Oceanography and Teaching

Tides themselves don’t induce (a lot of) mixing, only tides hitting topography do. An experiment.

mglessmer — Fri, 17 Aug 2018 07:33:50 +0000

As you might have noticed, the last couple of days I have been super excited to play with the large tanks at GFI in Bergen. But then there are also simple kitchen oceanography experiments that need doing that you can bring into your class with you, like for example one showing that tides and internal waves […]

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Waves in a density stratification. One of the most beautiful tank experiments I’ve ever seen.

mglessmer — Thu, 16 Aug 2018 16:23:38 +0000

It’s pretty impressive when a mountain moves through a stratification and generates lee waves. But what I find even more impressive: The waves that travel behind the mountain when the mountain is long gone. See here: This kind of stuff looks more like a numerical simulation than something actually happening in a tank, doesn’t it? […]

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Tank experiment: Lee waves in a fancy density (and dye) stratification

mglessmer — Thu, 16 Aug 2018 16:20:45 +0000

Did you seriously think we’d stop tank experiments with only 2-layer systems? Nooo! Today, the plan was to set up a continuous stratification, which I have been planning to do for many years. After fiddling with the setup all morning (do you have any idea how many fittings on all kinds of hoses are needed […]

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The one where it would help to understand the theory better (but still: awesome tank experiment!)

mglessmer — Thu, 16 Aug 2018 15:47:11 +0000

The main reason why we went to all the trouble of setting up a quasi-continuous stratification to pull our mountain through instead of sticking to the 2 layer system we used before was that we were expecting to see a tilt of the axis of the propagating phase. We did some calculations of the Brunt-Väisälä […]

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Dead water — the fancy experiment including Nansen himself

mglessmer — Thu, 16 Aug 2018 15:47:05 +0000

Now that we do have a really awesome 12-layer 6-color stratification, we obviously had to do the dead water experiment again. This time we chose to include a not-too-happy-looking Nansen on the ship, too! I love this even more than the one we did yesterday!

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“Dead water” or: ship-generated internal waves

mglessmer — Thu, 16 Aug 2018 04:15:00 +0000

And here is another experiment that can be done with the same stratification as the lee waves: Towing a ship to explore the phenomenon of “dead water”! Dead water is well known for anyone sailing on strong stratifications, i.e. in regions where there is a shallow fresh or brackish layer on top of a much […]

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Lee waves in the tank

mglessmer — Wed, 15 Aug 2018 19:18:57 +0000

Did you guess what we needed the stratification for? Yes — we are moving mountains again! :-) What we want to look at: How a current reacts to an obstacle in its way, especially a current in a stratification. But since it is really difficult to set up a current in a tank, let alone […]

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Kelvin-Helmholtz instabilities

mglessmer — Wed, 15 Aug 2018 18:08:26 +0000

I’m back at my happy place — the teaching lab at GFI in Bergen! :-) Here a quick look at what we’ve been doing today: Filling the large wave tank! With clear fresh water and then salty pink water that forms a layer below. As the pink water flows underneath the clear water, there is […]

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We discovered a new galaxy! Or at least a very pretty vortex

mglessmer — Thu, 26 Oct 2017 05:30:06 +0000

When we move our wall back and forth, we create very strong wing tip vortices that persist for quite a long time. Above, you see the vortex, lit by a laser sheet close to the surface. You can see the whole column rotating as one, that bright smudge below the swirl is the lower part […]

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“No one believes a theory, except the theorist. Everyone believes an experiment — except the experimenter.”

mglessmer — Tue, 24 Oct 2017 05:35:25 +0000

Different types of experiments, and why we use such a weirdly-shaped “Antarctica” and are happy with it. When we want to show people images of our model experiments in a tank, people often imagine that they will be shown cute little miniature landscapes, looking much like the ones you see for really fancy model train setups. And then they are […]

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