The resulting data is the video record and can be viewed on video recorders. In this photo taken at NASA Dryden Flight Research Center in 1989 you can see the F-18 HARV smoke and tuft flow visualization. The angle of attack here is 20 degrees. Here you can see vortex visualization being done in a wind tunnel for an FA-117 test. This picture was taken in the 40x80 wind tunnel at NASA's Full-scale Aeronautics Complex at Ames Research Center.
Smoke is introduced into the airstream and appears brown in color at the left of the nose area.
An argon-ion laser producing a green sheet of light is used to illuminate the vortex as the smoke is entrained in it. In the first photo tunnel lighting has been turned off to provide a dark visualization area. In this second photo tunnel lighting has been left on and you can see the vortex beginning to burst behind the green vortex slice. Notice also that it appears that the vortex is headed right for the vertical control surface or tail. This is the sort of thing design engineers worry about because it could cause premature failure.