Tag: eddies

This is the long version of the two full “low latitude, laminar, tropical Hadley circulation” and “baroclinic instability, eddying, extra-tropical circulation” experiments. A much shorter version (that also includes the end cases “no rotation” and “no thermal forcing”) can be found here. Several of my friends were planning on teaching with DIYnamics rotating tables right now. […]

The first experiment we ever ran with our DIYnamics rotating tank was using a cold beer bottle in the center of a rotating tank full or lukewarm water. This experiment is really interesting because, depending on the rotation of the tank, it will display different regimes. For small rotations we get a low latitude, laminar, tropical […]

On Thursday, I wrote about the thermally driven overturning circulation experiment that Torge and I did as past of our “dry theory 2 juicy reality” experiments, and mentioned that it was a non-rotating experiment in a class about rotating fluid dynamics. I showed you the rectangular tank, but we also used a cylindrical tank with […]

With all the rotating tank experiments I’ve been showing lately, one thing that comes up over and over again is the issue of solid body rotation. On our DIYnamics-inspired turntable for our “dry theory to juicy reality” project, Torge and I came up with a fun way to illustrate the importance of full body rotation in […]

Rotating experiments in your kitchen. Eddies, those large, rotating structures in the ocean, are pretty hard to imagine. Of course, you can see them on many different scales, so you can observe them for example in creeks, as shown below: If you can’t really spot them in the image above, check out this post for […]

Similarly to last Friday’s Kelvin-Helmholtz instabilities, observing swirls and eddies made from green fairy dust is not really what we are in Grenoble for. But are they pretty! And it is actually very interesting to observe the formation of eddies. If you look at the picture above and focus on the sharp edge “downstream” of the canyon, […]

I always love watching paddles in water, or ships in water, or ducks in water, or anything water, really, but on a wind-less day in Ratzeburg, Siska managed to create the beautiful eddies you see in the movie below, that survived well over half a minute out in the open lake! Beautiful.

My sister and I did a little sight-seeing tour in Hamburg the other day, and one of the most fascinating things I saw was — a diving duck. Now, that is not a reflection of how exciting the rest of Hamburg is, but if you don’t see it after watching the movie below, when you read […]

Eddies. Dips in the surface and shadows on the ground. I always get really fascinated by watching how eddies are generated by obstacles in a fluid. But it is especially exciting when you don’t only see the eddies because you see how they deform the surface, but when the water is clear enough so you […]

Or: fast inflow into nearly stagnant water body Did you ever notice how when certain ferries dock, they stop, already parallel to the dock, a couple of meters away from the dock and then just move sideways towards the dock? Usually they don’t even move passenger ferries any more, just use thrusters to keep them steady […]

Do you use a tide chart to find the best time for your Saturday walk, too? I showed you a vortex street on a plate formed by pulling a paint brush through sugary water as an example. Now today I want to show you the real thing: Instead of stagnant water and a moving object, I bring to […]

Kelvin-Helmholtz instabilities in a shear flow in Elbe river. Last week I talked about how I wanted to use the “Elbe” model in teaching. Here is another idea for an exercise: On the picture below you see Kelvin-Helmholtz instabilities. They might be kinda hard to make out from the picture, but there is a movie below where […]

You might think that three hours of canoe polo on a Saturday morning would be enough water for the day, but no.  As when I did the experiment for the “eddies in a jar” post a while back, sometimes I just need to do some cool oceanography. So last Saturday, this is what I did: I took a […]

Or: This is what happens to a hetonic explosion experiment without rotation. I’ve posted a lot while at JuniorAkademie a while back, so it is hard to believe there are still experiments from that time that I haven’t shown you. But I’ve probably only shown you about half the experiments we’ve done, and there are plenty more […]

There are currents and eddies and whirls everywhere! Today, Rolf showed us currents on soap bubbles. Check out the movie below for moving pictures!

Cooling and rotation combined. (deutscher Text unten) I can’t believe I haven’t blogged about this experiment before now! Pierre and I have conducted it a number of times, but somehow the documentation never happened. So here we go today! Martin and I ran the experiment for our own entertainment (oh the peace and quiet in […]

Or, an experiment on this blog often known as “slumping column”. (deutscher Text unten) If you don’t scale your tilting of frontal surfaces under rotation experiment correctly, you get a phenomenon called “hetonic explosion”: the formation of a cloud of baroclinic point vortices. From the densities, the rotation rate, the dimensions etc you can calculate the Rossby […]

Eddy in a rotating tank. This is an experiment that Pierre and I ran two years ago in Bergen but that – as I just realized – has not been featured on this blog before. Which is a pity, because it is a pretty cool experiment. Under rotation, vertical fronts with different densities on either […]

You can see “shadows” of eddies on the ground! As everybody who has ever watched a bath tub drain knows – eddies do lead to a deformation of the water’s surface. Here is an example of what that looks like in the real world: In case you don’t see the eddies like pearls on a string […]