Sound Radiation Characteristics of a Rectangular Duct with Flexible Walls

Table 6

Radiation efficiency slopes of strongly coupled structural modes.

Mode	Frequency (Hz)	Analytical (dB/decade)	Numerical (dB/decade)
1	99.26	19.42	18.90
2	114.65	39.25	39.00
11	224.84	17.27	16.96
14	249.85	18.72	18.74
18	278.08	16.75	16.90
21	306.25	38.05	38.69