Confluence of Danube and Morava river.

Watching the shear flow on Elbe river the other day, I was reminded of another shear flow which I had watched a long time ago. In 2009, J and I went to Bratislava in Slovakia, and from there did a trip to Devín castle.

What you see below is the confluence of the Danube and Morava rivers (with the muddy water coming in from the right).

Confluence of Danube and Morava river near Bratislava

I found it fascinating to watch the muddy water coming in, and then being forced downstream by the much faster flowing Danube. In the picture above you can see the sharp corner and then the front carrying instabilities caused by the strong shear.

Unfortunately, this was at a time when I didn’t even dream of ever blogging, so I don’t have more pictures of the shear instabilities. But I have a better picture of the front in the more stagnant part of the flow:

Devín castle

Fascinating how such a sharp feature can persist! Both in almost stagnant water (wouldn’t boats going through, or fish, or something mix it up?) as well as fast-flowing (there are clearly huge instabilities on the front, why don’t they mix more efficiently?). Plus the muddy water should warm up faster than the green-ish water, so why doesn’t the muddy water form a surface layer, at least in the stagnant part?

Digging out these pictures really was a journey down memory lane. First, I had to dig out my old laptop. Which was the second laptop I ever owned, but still it’s huge. Then I had to remember how to get into the correct partition on that laptop. Funny how somehow my fingers remembered the password to the computer based on the different shape of keyboard, maybe? I could type it, but I would not have been able to spell it out. And then I had to somehow get the pictures off! Not easy, I can tell you. But it is incredible how fast technology advances. I did have a good digital camera then, and I uploaded the pictures at full resolution. So that is really all there is to look at. I am really curious what digital photography will be like in another 6 or so years…