 This
page shows a model of the Concorde
in a water tunnel. The red dye streamer, which is introduced
near the apex of the modified delta, goes into the forward primary vortex. Farther downstream a green streamer is introduced
and it wraps around the red streamer. If this were a simple
delta (with strait leading edges) the green streamer would go into the
outer layers of the vortex but, because of the difference in sweep between
the for and aft parts, it goes into a new vortex with the same direction of rotation which wraps around
the vortex from the forward section. Notice that the
core is pretty stable and the red streamer is still fairly coherent some
distance downstream of the trailing edge. The green streamer
however is getting fuzzy some distance before the trailing edge indicating
that it is nearing the end of it's useful life (it's burst point).
Photograph courtesy of Office National d'Etudes
et Recherches Aeronautiques |