Tag: tank experiment

A project near and dear to my heart is using the DIYnamics rotating tank experiments in across-course collaborations. “Older” students, who did experiments the previous year, are trained to then act as guides to “younger” students when they do experiments for the first time, thus lowering the threshold of engaging with equipment, acting as role […]

Last week, Kjersti Daae and I gave a virtual presentation at the iSSOTL conference, and here is a short summary. We presented an ongoing teaching innovation project, funded by Olsen legat and conducted together with Jakob Skavang, Elin Darelius and Camille Li, that we started last year at the Geophysical Institute in Bergen: Bringing together […]

Several of my friends were planning on teaching with DIYnamics rotating tables right now. Unfortunately, that’s currently impossible. Fortunately, though, I have one at home and enjoy playing with it enough that I’m Playing with it Making videos of me playing with it Putting the videos on the internet Going to do video calls with my […]

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 […]

Several of my friends were planning on teaching with DIYnamics rotating tables right now. Unfortunately, that’s currently impossible. Fortunately, though, I have one at home and enjoy playing with it enough that I’m Playing with it Making videos of me playing with it Putting the videos on the internet Going to do video calls with my […]

Several of my friends were planning on teaching with DIYnamics rotating tables right now. Unfortunately, that’s currently impossible. Fortunately, though, I have one at home and enjoy playing with it enough that I’m Playing with it Making videos of me playing with it Putting the videos on the internet Going to do video calls with my […]

It’s #KitchenOceanography season! For example in Prof. Tessa M Hill‘s class at UC Davis. Last week, her student Robert Dellinger posted a video of an overturning circulation on Twitter that got me super excited (not only because as of now, April 15th, it has 70 retweets and 309 likes. That’s orders of magnitude more successful than any […]

In addition to our four DIYnamics-inspired rotating tanks, we now have a highly professional rotating table with SO MANY options! And also so much unboxing and constructing and trouble-shooting to do before it works. But we finished the first successful test: wanna see some rotating coffee in which milk is added? Then check this out! […]

Today was the second day of tank experiments in Torge’s and my “dry theory 2 juicy reality” teaching innovation project. While that project is mainly about bringing rotating tanks into the theoretical teaching of ocean and atmosphere dynamics, today we started with the non-rotating case of a thermally driven overturning circulation. Very easy setup: A […]

This is seriously one of the easiest tank experiments I have ever run! And I have been completely overthinking it for the last couple of weeks. Quick reminder: This is what we think hope will happen: On a slope, melt water from a dyed ice cube will sink, creating a Taylor column that will be driven […]

For both of my tank experiment projects, in Bergen and in Kiel, we want to develop a Rossby wave demonstration. So here are my notes on three setups we are considering, but before actually having tried any of the experiments. Background on Rossby waves I recently showed that rotating fluids behave fundamentally differently from non-rotating […]

It has been a long time in the making, but finally we have a nice fjord circulation in our tank! Pierre and I tried to improve it 6 years ago, Steffi, Ailin and I have been working on it for a couple of days last August, then finally this morning, Steffi and I tried again — […]

Inspired by the article “Affordable Rotating Fluid Demonstrations for Geoscience Education: the DIYnamics Project” by the Hill et al. (2018), I spent a fun Sunday afternoon with my friends Joke and Torge in their kitchen, playing with Legos, water and food dye. Turns out building a rotating table isn’t as easy as we had hoped, because my […]

I’d love your input: If your student lab for GFD tank experiments had to downsize, but you had to present a “wish list” for a smaller replacement, what would be on that list? Below are my considerations, but I would be super grateful for any additional input or comments! :-) Background and “boundary conditions” The […]

How will lee waves look differently if we are using the asymmetrical mountain instead of the symmetric one? And is symmetry actually important at all or are we just looking at different slopes downstream while the upstream slope doesn’t have an influence on the wave field? After admitting I had only ever used the symmetrical […]

This blog post is meant as guideline if someone other than me might have to set up this demonstration at some point… Have fun! :-) Lee waves Lee waves are the kind of waves that can be observed downwind of a mountain in the clouds, or downstream of an obstacle in a current as a […]

When setting up the stratification for the Nansen “dead water” demo (that we’ll show later today, and until then I am not allowed to share any videos, sorry!), I went into a meeting after filling in layer 4 (the then lowest). When I came back, I wanted to fill in layer 5 as the new […]

So you thought filling water into a tank was boring? Not on my watch! This is how we fill up the tank: Through a hole at the bottom. Which leads to a very nice fountain that slowly submerges as the water level rises: …and to tons of nice waves, which are great to observe! Propagation […]

On the coolest process in oceanography. My favorite oceanographic process, as all of my students and many of my acquaintances know, is double-diffusive mixing. Look at how awesome it is: Double-diffusive mixing happens because heat and salt’s molecular diffusion are very different: Heat diffuses about a factor 100 faster than salt. This can lead to […]

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 […]

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 […]

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!

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 […]

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 […]

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 […]

“The easiest” in the title of this page is to show the contrast to a “slightly more complicated” version here. Background One of the first concepts people hear about in the context of ocean and climate is the “great conveyor belt”. The great conveyor belt is a very simplified concept of the global ocean circulation, which is depicted as […]

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 […]

Explore how melting of ice cubes floating in water is influenced by the salinity of the water. Important oceanographic concepts like density and density driven currents are visualized and can be discussed on the basis of this experiment. Context Audience This hands-on experiment is suited for many different audiences and can be used to achieve a wealth […]

When talking about oceanographic tank experiments that are designed to show features of the real ocean, many people hope for tiny model oceans in a tank, analogous to the landscapes in model train sets. Except even tinier (and cuter), of course, because the ocean is still pretty big and needs to fit in the tank. […]

And really high order ones, too! On Monday, I showed you a movie on wave generation in Hamburg Ship Model Basin (HSVA)’s wave tank. At the end of that movie, we see that the wave energy is being dissipated by a “beach”. Well, we actually see that some of the energy is reflected in those cute little […]

When a higher-order effect suddenly becomes important. During our excursion to Hamburg Ship Model Basin (HSVA), one of the experiments we ran was on Stokes drift. You can already see in that post’s movie that there is some swimming thing moving down the tank in the direction of wave propagation, but of course we had to quantify. “Experiment” sounds too […]

Excursion to Hamburg Ship Model Basin. I recently got to join a class on their excursion to Hamburg Ship Model Basin (HSVA, “Hamburgische Schiffbau-Versuchsanstalt” klingt so viel besser!). Those are amazing facilities and shipbuilding students are always excited to go there and get a glimpse at all the exciting research going on. Since they are working on […]

Rotating experiments in your kitchen. Do you know those Saturday mornings when you wake up and just know that you have to do oceanography experiments? I had one of those last weekend. Unfortunately, I didn’t have a rotating table at hand, but luckily most of my experiments work better than the exploding water balloon time-lapse […]

Because I am getting sick of stratifications not working out the way I planned them. Creating stratifications, especially continuous stratifications, is a pain. Since I wanted a nice stratification for an experiment recently, I finally decided to do a literature search on how the professionals create their stratifications. And the one method that was mentioned over […]

Because sometimes it’s easier to control a computer than rotation, salinity, water and dye. After looking at a non-rotating cylinder collapse the other day, it is time to look at proper hetonic explosions (you know? The experiment on the rotating tank where a denser column of water at the center of the tank is released when […]

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 […]

Because sometimes one overflow simply isn’t enough. Finn’s group came up with – and ran – an overflow experiment with many different densities and even more colors. While the movie didn’t turn out too well, the idea was pretty awesome. Rolf went ahead and modeled the experiment right away. And because the plume didn’t go across […]

Water running uphill during spin-down – how much more awesome can it get? After hours, when all but the most curious students had left, Rolf and I ran another collapsing cylinder experiment, this time on Rolf’s old disk player turned rotating table. Rolf has a cone-inset for the round tank, and we set a cylinder […]

My absolute favorite experiment ever: salt fingering. I know I’ve said it before about another experiment, even today, but this is my absolute favorite experiment and I still get endlessly fascinated. I’ve written about salt fingering before, and given tips on run the experiment, but today we tried a different setup. We used the same […]

Trying to tweak conditions to force a set number of vortices. We’ve done the hetonic explosion again. This time the group was super careful to calculate the Rossby radius correctly, and then to set up the experiment accordingly. We aimed for a single column like in our tilting of a frontal surface under rotation experiment. We […]

One of my all-time favorite experiments. The salt group got a bit bored from watching ice cubes melt, so I suggested they look at temperature differences for a change, and they ran the “leaking bottles” experiment. Watch a movie combining their four different setups below!

The unavoidable tank experiment when playing with Rolf ;-) After the first attempt – embarrassingly shown by the instructors – failed miserably, one of our groups ran the overflow experiment successfully. Watch movie below to see the experiment in all its beauty.

A wind stress is applied to the surface to cause mixing. This is an experiment that I have been wanting to do for a long time, but somehow it never worked out before. But last night Martin and I finally ran it! We ran two experiments, one after the other. In the first one, we […]

Creating waves in a tank. (deutscher Text unten) In the big tank, we have a paddle that is really good for making big waves. And if you create them in just the right way, they reflect at the back of the tank to meet up with the incoming waves right above the “sandbank” we put in […]

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 […]

Plus all kinds of dyes. (deutscher Text unten) Using the continuous salinity stratification created yesterday, Rolf and Daniel conducted a really cool experiment: They forced internal waves and watched them develop. I’ve converted their movie into a time-lapse; watch it below. Mit der kontinuierlichen Salzschichtung, die Daniel und Rolf gestern gebastelt haben, haben sie danach […]

And watching internal waves – a data-model comparison. (deutscher Text unten) In an experiment similar to the one done by the group looking at the effects of temperature and salinity on density, the wave group, supported by Rolf, started looking at how to create a continuous stratification through internal wave action. Two water masses, one saline […]

Removing a barrier between waters of different densities and watching what happens. (deutscher Text unten) Today, one of the groups performed a classical experiment (shown for example here) – but the awesome thing is that they came up with the planning pretty much by themselves in order to determine the effects of temperature and salinity […]

A first attempt where gravity (due to a tilted axis of rotation) replaces the pull of the moon. (deutscher Text unten) The movie contains both a view from a co-rotating camera and from a non-rotating camera. Gezeiten im rotierenden Tank, in dem die Anziehung durch den Mond durch Erdanziehung simuliert wird, die wir durch eine […]

Luckily I’m not the only one believing that we absolutely need remotely controlled boats! – Zum Glück bin ich nicht die Einzige, die findet, dass wir ferngesteuerte Boote brauchen! Mein Boot hat Hochkonjunktur. D. kann es in einem Tank wenden, der nur etwa 1.5 mal so breit ist wie das Boot lang! Das kann man […]

Cooling on one end of the tank, heating on the other: A temperature-driven overturning. [deutscher Text unten] Always one of my favorite experiments – the overturning experiment (and more, and more). Unsere “Klima und Strömungen”-Gruppe hat heute ausprobiert, wie man in einem Tank eine Umwälzströmung erzeugen kann, indem man an einem Ende wärmt und am anderen […]

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 […]

Ha, this is a bad pun. We are modeling the Denmark Strait Overflow – but in a non-numerical, small-scale-and-playdough kind of way. More than a year ago, Kjetil and I ran that experiment with a group of high-school students and when writing a post about a much more sophisticated version of this experiment I realized I […]

Trying to create rogue waves in the bath tub of the infamous “red house”. As a part of their projects, students in the CMM31 in Isafjördur course had to conduct an experiment, document and interpret it. One of the students, Silvia, chose to create rogue waves in the bath tub of the “red house”, one […]

The experiment we run to discuss the velocity of shallow water waves. In this post, I discussed how it took us several years to modify an experiment to make it both student and teacher-friendly. But what can you actually see in that experiment? The movies below show the type of standing waves that are excited […]

Improving one of the experiments run in the GEOF130 lab. One experiment that has been run in GEOF130 forever is the “standing wave”, where a wave is excited in a long and narrow tank and then, for different water depths, the period is measured and the velocity calculated in order to compare it to the […]

A solution for the siphon problem of the fjord circulation experiment. After having run the fjord circulation experiments for several years in a row with several groups of students each year, Pierre and I finally figured out a good way to keep the water level in the tank constant. As you might remember from the […]

Tank experiment on a typical circulation in a fjord. Traditionally, a fjord circulation experiment has been done in GEOF130’s student practicals. Pierre and I recently met up to test-run the experiment before it will be run in this year’s course. This is the setup of the experiment: A long and narrow tank, filled with salt water, […]

A movie focusing on details of the lee waves in the tank. In this post, we investigated lee waves in a tank in a general way. Here, I want to show a detail of those lee waves: In this movie, the concept of hydraulic control becomes visible. On the upstream side of the mountain, the […]

How internal waves in the ocean can be spotted on the surface. Under certain conditions, internal waves in the ocean can be spotted at the ocean’s surface due to changes in surface roughness or to the movement of floating foam or debris. They can be spotted if half their wavelength is longer than the distance […]

Lee wave experiment in a large tank with a moving mountain. In this previous post, we talked about internal waves in a very simple experiment. But Geophysical Institute has a great tank to do lee wave experiments with that I want to present here (although it doesn’t seem to be clear what will happen to the […]