In their experiments, Saffman and Taylor noted that the value of
decreased rapidly to 1/2 as the flow speed increased, and
remained at that fixed value for all high speeds (i.e. speeds such
that 
). This result occurred consistently for
different fluids with different viscosities; in particular, observing
different systems showed that the value of is dependent on
the dimensionless parameter 
. Saffman and Taylor were unable
to explain this phenomena.
They also found that a finger which was slightly larger than the adjacent fingers at a certain point in time proceeded to spread sideways and grow at the expense of the adjacent fingers, resulting in one large finger and a small finger on either side. Faber [3] noted that eventually the system will evolve to a state where there is one single finger, and Homsy [4] explained that this effect results from the pressure gradient in the more viscous fluid being more favorable to the growth of the larger fingers than the smaller fingers.