The first part of the talk reviews results on the line-driven instability of OB star winds. This instability breaks the smooth flow into sequences of strong reverse shocks, which compress the gas into dense clouds. The observed X-ray emission from OB stars is direct evidence for chaotic wind structure. While the reverse shocks themselves cannot account for the large observed X-ray fluxes, recent numerical models show that mutual collisions between two different families of wind clouds can reproduce the observed X-ray spectra.
In the second part I discuss recent results on line-driven winds from
accretion disks, especially in cataclysmic variables. Due to the initial
growth of gravity as function of height above the disk (`gravity hill'),
the solutions to the Euler equation show interesting properties, e.g.,
split into an inner and outer disk wind. The tilt angle between wind and
disk is given by the temperature run in the disk. For realistic T(r), the
wind is bi-polar, in accord with observations.