Buoyancy – the beauty of heating water

In our dormitory the room is heated by heating elements in the floor, such that it’s comfortable to walk around. I’m used to having my water bottles on the floor, but because of the heat, the water gets warm quite fast.
I was wondering how the water actually is heated. Is the water just heated from the bottom up and the temperature of the water perfectly proportional to the distance from the bottom? I had a suspicion that it would be more complicated (water is ALWAYS complicated), because warmer water is lighter than colder water, so the warm water would try to raise to the top, which would give some turbulence.
To get an answer I used COMSOL, a simulation software, to get a simulation of the heating of the water. And this is the result (large file, may take a while…):


Pretty, isn’t it?

When I started, I tried to model the bottle as a 2D-container, but that would be the equivalent of a long rectangular box. The result is almost more interesting than the 3D-model:


Remember these images next time you put a glass of cold water on a table.

Comments are closed.