Duct modes in linear shear flow (hard wall, 2D)
U
V
ω
= 13,
n
= 1
ω
= 13,
n
= 2
ω
= 13,
n
= 3
ω
= 13,
n
= 4
ω
= 2,
n
= -1
ω
= 4,
n
= -1
(see "Sound Propagation in Slowly Varying 2D Duct with Shear Flow", AIAA-2016-2925)