is the material derivative of the Lagrangian motion of a fluid parcel located at
This ABС flow was analyzed by Dombre et al. 1986 who gave it the name A-B-C because this example was independently introduced by Arnold (1965) and Childress (1970) as an interesting class of Beltrami flows.
For some values of the parameters, e.g., A=B=0, this flow is very simple because particle trajectories are helical screw lines.
For some other values of the parameters, however, these flows are ergodic and particle trajectories are everywhere dense.
[4] It is named after Vladimir Arnold, Eugenio Beltrami, and Stephen Childress.