Intrinsic and extrinsic vortex nucleation mechanisms in the flow Feodor Kusmartsev 2134/1230 https://repository.lboro.ac.uk/articles/preprint/Intrinsic_and_extrinsic_vortex_nucleation_mechanisms_in_the_flow/9411269 We propose very general vortex nucleation mechanisms analogous to a hydrodynamic instability and calculate associated critical velocity in agreement with experiments. The creation of vortices via extrinsic mechanism is driven by a formation of the surface vorticity sheet created by the flow, which reaches a critical size. Such a sheet screens an attraction of a half-vortex ring to the wall, the barrier for the vortex nucleation disappears and the vortex nucleation is started. In the intrinsic mechanism the creation of a big vortex ring, which transforms into the vortex, is driven by a fluctuative generation of small vortex rings 2006-04-12 12:30:06 untagged Physical Sciences not elsewhere classified