Sound Radiation Characteristics of a Rectangular Duct with Flexible Walls

Table 7

Comparison of the radiation efficiency slopes for duct modes and simply supported plate modes.

Group	Duct mode	Duct mode analytical (dB/decade)	Duct mode numerical (dB/decade)	Simply supported plate mode (dB/decade)
1		19	19	19
2		41	41	39
3		37	39	39
4		57	58	54