There is a dramatic kink in B due to a change in the increase of the area at a certain location in the plume.
The kink in B affects the kappa calculation but the average kappa I used in the liftoff length comparison didn’t include the high kappas near the mouth.
The average kappa calculation averages the kappas between the red and blue stars. The location of the red and blue stars in the plume is shown in the bottom figure.
River Research 