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).
<a href="//commons.wikimedia.org/w/index.php?title=User:BavandK&amp;action=edit&amp;redlink=1" class="new" title="User:BavandK (page does not exist)">Bavand Keshavarz</a>
CC BY 4.0
<span class="int-own-work" lang="en">Own work</span>