Physics and Gas Dynamics of Wind-Blown Bubbles

We review the recent hydrodynamic modelling of wind-blown bubbles (WBB) which are result of interaction of a stellar wind with the circumstellar matter or the wind(s) emitted during the previous stages of the central star evolution. The much faster computers becoming available in the last decade allow a more complete picture of the physics of these objects to be built. Recent hydrodynamic models are capable of treating in detail different mechanisms as radiative plasma cooling, electron thermal conduction and the effects of magnetic fields. We discuss the various mechanisms proposed for shaping these objects and we emphasize on the problems related to the development of various instabilities and the X-ray emission from WBB.