Two-dimensional models of stellar wind bubbles

Hydrodynamical models of dense circumstellar clumps accelerated by supersonic stellar winds are obtained. Dimensions, densities and velocities of the models are representative of conditions that are likely to be met by Herbig-Haro objects. It is shown that the existing analytical estimates of the acceleration efficiency are too optimistic, what has its source in neglected hydrodynamical effects. Radiative models lead to a poor acceleration of the clumps, or to their disruption. The implications of these facts are discussed in relation to different theories concerning Herbig-Haro objects. 23 refs., 5 figs. (author)