Past exam of the mathematics course of the University of Cambridge / 2018 / iii / Paper 331 / 1 / a / i / Solution

For irrotational flow, ${\mathbf{u}}_j=\nabla {\varphi }_j$. An impermeable stationary horizontal wall has zero normal velocity, so the kinematic boundary condition isNo tangential no-slip condition is imposed on these inviscid fluids.