Lecture 4: Euler flows and vorticity.

Euler flows. Local characterization of vorticity, circulation, Kelvin's theorem. The vorticity equation. The Bior-Savart law for velocity given vorticity. Cauchy's representation of vorticity kinematics. Helmhotz' laws and vortex stretching. The issue of global regularity in 3D. The Rankine combined vortex.

Suggested reading: