Vorticity, a measure of the local rotation or swirling motion in a fluid, has long been studied by physicists and mathematicians. The dynamics of vorticity is governed by the famed Navier-Stokes ...

Shaking a liquid fast enough allows it to levitate, and a toy boat can float on top of the levitating fluid – or upside down beneath it. When a viscous fluid like silicone oil is shaken up and down ...