Fluid Dynamic Aspects of Protostellar Disks Formation

An analysis is presented of fluid dynamic aspects of the interaction between a disk and the infall of material from a surrounding non-magnetized rotating molecular cloud. The study put emphasis on the accretion shock formed in the vicinity of the disk and the post-shock flow field. This post-shock flow is considered parallel to the disk symmetry plane involving a super-Keplerian azimuthal velocity field v similar to 1/r (potential vortex). The relative rotation between fluid and the nearly Keplerian rotating thin disk induces along its symmetry plane a boundary layer capable of transporting large quantities of fluid inward. This radial flow results in an axial flow i.e., a mass ejection from the boundary layer with axial jet flow velocities of up to about 300 km s(-1).