  We formulate a generalisation of the blast-wave model which is suitable for
the description of higher order azimuthal anisotropies of the hadron
production. The model includes anisotropy in the density profile as well as an
anisotropy in the transverse expansion velocity field. We then study how these
two kinds of anisotropies influence the single-particle distributions and the
correlation radii of two-particle correlation functions. Particularly we focus
on the third-order anisotropy and consideration is given to the averaging over
different orientation of the event plane.
