Mode matching solution of reflection and transmission
through duct junction from radius 1 to 0.7

ka = 4, m = 0, n = 1 (right-running)

ka = 4, m = 0, n = -1 (left-running)

ka = 10, m = 0, n = 1 (right-running)

ka = 10, m = 0, n= -1 (left-running)