File:Rolling Around A Spinning Top (Montage).jpg

English: Using dye injection, we visualize the flow around a spinning top as it rotates inside a liquid. The circular motion of fluid elements generates centripetal acceleration. This ignites secondary flows and generates toroidal vortices that roll up around the geometry in an ever-spinning spiral. These mesmerizing patterns are “Like a circle in a spiral, Like a wheel within a wheel, Never ending or beginning, On an ever-spinning reel, As the images unwind, Like the circles that you find, In the windmills of your mind” (poem by Allan and Marilyn Bergman). This montage of images shows how the injected dye gradually gets trapped inside the spiral of these toroidal vortices.