case

h/c

U r e f ( m / s )

Re

frequency (Hz)

reduced frequency ( k = ω c / 2 U r e f )

2a

68.6

5 × 106

0.5, 1.0, 1.5

0.010, 0.021, 0.031

2b

0.8

68.6

5 × 106

1.0, 1.5

0.021, 0.031