VORTEX BURSTING IN FLIGHT
NASA Dryden Flight Research Center
In this photo taken at NASA Dryden Flight Research Center in 1989 smoke and tuft flow visualization,
the vortex formed over the front part of the fuselage on NASA's F-18 HARV is made visible.
The angle of attack here is 20 degrees. In the region over the wing, the vortex
is seen to grow suddenly in diameter -- this process is called vortex bursting.
The vortex interacts with the boundary layer on the wing, and vortex bursting
can greatly alter the flow pattern. Some of the flow pattern over the
wing and fuselage is made visible using tufts, which are small pieces
of string or similar material. Since they have very small stiffness or
inertia, they give an indication of the instantaneous flow direction in
the region of the flow near the surface.