  The squirmer is a simple yet instructive model for microswimmers, which
employs an effective slip velocity on the surface of a spherical swimmer to
describe its self-propulsion. We solve the hydrodynamic flow problem with the
lattice Boltzmann (LB) method, which is well-suited for time-dependent problems
involving complex boundary conditions. Incorporating the squirmer into LB is
relatively straight-forward, but requires an unexpectedly fine grid resolution
to capture the physical flow fields and behaviors accurately. We demonstrate
this using four basic hydrodynamic tests: Two for the far-field flow---accuracy
of the hydrodynamic moments and squirmer-squirmer interactions---and two that
require the near field to be accurately resolved---a squirmer confined to a
tube and one scattering off a spherical obstacle---which LB is capable of doing
down to the grid resolution. We find good agreement with (numerical) results
obtained using other hydrodynamic solvers in the same geometries and identify a
minimum required resolution to achieve this reproduction. We discuss our
algorithm in the context of other hydrodynamic solvers and present an outlook
on its application to multi-squirmer problems.
