Pinnau – Adventures in Oceanography and Teaching

Observing hydrodynamic phenomena on a creek

mglessmer — Thu, 11 Feb 2016 11:48:29 +0000

Looking at a creek on a Sunday stroll, and seeing lots and lots of concepts from hydrodynamics class. For example below, you see waves radiating from each of the ducks. And you see interference of waves from all those ducks. What happens if the ducks bring their waves closer? At some point, all those waves from […]

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Streak lines?

mglessmer — Wed, 27 May 2015 09:07:38 +0000

A common problem in hydrodynamics is to distinguish between all the different kinds of lines that characterize a flow field: Stream lines, streak lines, path lines, time lines, and probably more that I can’t think of right now. A common way to think of streak lines is that they are similar to hairs caught in the flow of […]

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On vorticity

mglessmer — Mon, 25 May 2015 09:37:51 +0000

I’ve promised a long time ago to write a post on vorticity (Hallo Geli! :-)). So here it comes! Vorticity is one of the concepts in oceanography that is often taught via its mathematical formulation, and which is therefore pretty difficult to grasp for those of us with less mathematical training. But it’s also a […]

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Eddy generation and optics.

mglessmer — Fri, 24 Apr 2015 11:14:35 +0000

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 […]

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Waves on a current

mglessmer — Mon, 20 Apr 2015 11:36:14 +0000

When you throw a stick in the water and the waves don’t form circles. Throwing something in the water usually results in waves traveling out in circles from the point of impact. But if you throw your stick into a current, the waves get distorted. Watch the movie below! Slightly confusing that the stick drifts […]

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Surface tension and water striders

mglessmer — Fri, 16 May 2014 05:47:21 +0000

How water striders can walk on water. More pictures from the same spot at the banks of the Pinnau. Looking more closely, you can see the water strider: And now a real close-up from the pond in my parents’ garden (because those pesky little bugs are too fast to take pictures off when you are […]

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Refraction of light in water – sticks and lenses.

mglessmer — Wed, 14 May 2014 05:29:35 +0000

Deformation in the water surface focussing light. Talking about how a deformation in the surface leads to light being focussed in different ways here and here, another example came to my mind. Remember how my mom and I were watching the standing waves at the Pinnau a while back? That was the same place where we […]

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Standing waves

mglessmer — Fri, 02 May 2014 05:21:27 +0000

Standing waves caused by rocks in a current. I am incredibly fascinated by standing waves. The standing waves are caused by rocks sitting in a current. From the pictures below it is not really clear where those rocks are situated, whether they are upstream of all this wave action or in the focal point of […]

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