HYDRODYNAMIC MODELS OF PLANETARY-NEBULAE

This article tries to give a short review of the hydrodynamic modellin g of Planetary Nebulae to date. I start by discussing the types of obs ervations the modelling aims to reproduce and then discuss the results of different types of models. First the 'simplified' models in which evolutionary changes in the stellar properties are neglected, then the 'evolutionary' models in which these effects are taken into account. The 'simplified' models call reproduce single shell nebulae with the r ight kinematic properties. The 'evolutionary' models can reproduce mul tiple shells and some of the kinematic and morphological differences b etween various ions. I also briefly discuss some of the difficulties w hich have not been addressed and/or solved by the numerical modelling, such as the point-symmetric nebulae, some of the collimated phenomena , and clumpiness.