11. Boundary conditions are imposed at vortex ring level. 12. Vortex rings can be triangular or quadrilateral, but most importantly, they can be slender or solid.13. The diaphragm quickly pushes a quantity of air out of the open end, creating a vortex ring . 14. That configuration caused the Osprey to flip over when it entered vortex ring state, experts have said. 15. That accident was blamed in part on human error and on something called " vortex ring state ." 16. But they also made 28 recommendations to address the problem of vortex ring state and other aerodynamic issues. 17. Thus, a vortex ring can carry mass much further and with less dispersion than a jet of fluid. 18. This is how a smoker expels smoke rings from the mouth, and how most vortex ring toys work. 19. The panel strongly recommended pilot training to avoid vortex ring state and installation of a cockpit warning system. 20. That accident was blamed in part on human error and in part on the vortex ring state condition.
