Kelvin-Helmholtz instability
A flat vortex sheet of constant strength
separates two streams of fluid moving in
opposite directions.
When the sheet is given a small perturbation,
it rolls up into a periodic array of spiral vortices.
The simulations below use a regularized point vortex method
to track the motion of the sheet.
References
Krasny, R.
(1986)
Desingularization of periodic vortex sheet roll-up,
J. Comput. Phys. 65, 292-313
Krasny, R.
(1988)
Numerical simulation of vortex sheet evolution,
Proc. IUTAM Symp. on "Fundamental Aspects of Vortex Motion",
H. Hasimoto & T. Kambe (eds.), Fluid Dyn. Res. 3, 93-97,
North-Holland