I was curious as cousin commenters, and this helped make sense of things (and connect a few completely unrelated intuitions) As long as the effects of viscos

I was curious as cousin commenters, and this helped make sense of things (and connect a few completely unrelated intuitions) As long as the effects of viscosity and diffusion are negligible, the fluid in a moving vortex is carried along with it. In particular, the fluid in the core (and matter trapped by it) tends to remain in the core as the vortex moves about. This is a consequence of Helmholtz's second theorem. Thus vortices (unlike surface waves and pressure waves) can transport mass, energy and momentum over considerable distances compared to their size, with surprisingly little dispersion. This effect is demonstrated by smoke rings and exploited in vortex ring toys and guns. https://en.wikipedia.org/wiki/Vortex#Evolution https://en.wikipedia.org/wiki/Vortex#Evolution