Clumpy Flows in Protoplanetary and Planetary Nebulae

Many astrophysical flows occur in inhomogeneous media. We briefly discuss some general properties of the adiabatic and radiative inhomogeneous systems and discuss the relevance of those properties to the planetary nebulae systems. We then focus on radiative hypersonic bullets and the applicability of this model to planetary and protoplanetary systems such as CRL 618, NGC 6543, Hen 3-1475.