Lecture 6: Potential flow in 2 and 3 dimensions.

Uniqueness of potential flows. Fundamental solutions of Laplace's equation in 3D as a fluid sources and sinks.
Non-reversible character in real fluids. The Rankine fairing. Calculation of force from momentum integral.
A model of flow past an airship. Butler sphere theorem and flow past a sphere.
D'Alembert's paradox from kinetic energy.

Irrotational flow in 2D using complex potentials. Blasius theorem for the force on an aerofoil.

Suggested reading: The sections given here are somewhat technical, and are suggested only
as a supplement to the lecture for students ith some familiarity with potential theory..