  Liquid impact problems for hemispherical fluid domain are considered. By
using the concept of pressure impulse we show that the solution of the flow
induced by the impact is reduced to the derivation of Laplace's equation in
spherical coordinates with Dirichlet and Neumann boundary conditions. The
structure of the flow at the impact moment is deduced from the spherical
harmonics representation of the solution. In particular we show that the slip
velocity has a logarithmic singularity at the contact line. The theoretical
predictions are in very good agreement both qualitatively and quantitatively
with the first time step of a numerical simulation with a Navier-Stokes solver
named Gerris.
