The Lamb-Oseen Vortex and Paint Marbling

Just published The Lamb-Oseen Vortex and Paint Marbling on arXiv.

The image to the left shows the decay with time of the Lamb-Oseen vortex (starting from an impulse of circulation at the center point).

The image to the right shows the same vortex, but with exponentially increasing time.  The rotational shear propagates to larger and larger orbits while the center returns to rest.  While this animation returns to its original position, it could come to rest at any angle controlled by the magnitude of the initial circulation.

More about mathematical marbling.