A jet of viscous liquid impinging
on a bath of the same liquid.
As the jet speed is increased above a
threshold velocity, a cylindrical sheet of
air is entrained, see:
É. Lorenceau, D. Quéré, and J. Eggers, Air entrainment by a visocus jet plunging into a bath ,
Phys. Rev. Lett. 93 , 254501 (2004)
