  In this article, we analyse a stabilised equal-order finite element
approximation for the Stokes equations on anisotropic meshes. In particular, we
allow arbitrary anisotropies in a sub-domain, for example along the boundary of
the domain, with the only condition that a maximum angle is fulfilled in each
element.This discretisation is motivated by applications on moving domains as
arising e.g. in fluid-structure interaction or multiphase-flow problems. To
deal with the anisotropies, we define a modification of the original Continuous
Interior Penalty stabilisation approach. We show analytically the discrete
stability of the method and convergence of order ${\cal O}(h^{3/2})$ in the
energy norm and ${\cal O}(h^{5/2})$ in the $L^2$-norm of the velocities. We
present numerical examples for a linear Stokes problem and for a non-linear
fluid-structure interaction problem, that substantiate the analytical results
and show the capabilities of the approach.
