In a previous post I shared a video on mixing and unmixing of fluids. This time I share with you an image I took of my coffee. With some milk fluid dynamics created amazing vortices. Following it is an animation of the time evolution of the vortices.
“Milk vortices” by Astrobob – Own work. Licensed under CC BY-SA 4.0 via Commons.
In the Netherlands, some of the windmills used to drain the polders at Kinderdijk have been replaced by modern Archimedes screws.
Image by: M.A. Wijngaarden
License: CC Attribution-Share Alike 2.5 Generic license.