Investigation of Low-Frequency Sound Radiation Characteristics and Active Control Mechanism of a Finite Cylindrical Shell

Table 1

Comparison of values of the natural frequency (Hz) for a shell L = 1.284 m, a = 0.18 m, and h = 0.003 m.

m	n	Air			Water
		Ref. [39]	Ref. [40]	Present	Ref. [39]	Ref. [40]	Present
1	5	542.3	—	542.8	351.6	—	343
1	4	340.5	336.6	340.5	205.6	200.9	202
1	2	195.3	194.0	197.1	98.2	97.5	99
1	3	199.0	198.0	198.8	110.9	108.7	109
2	2	635.8	—	654.7	328.9	—	339
2	3	386.5	387.0	388.5	218.2	217.0	217
2	4	403.5	403.0	403.4	245.8	241.3	242
2	5	570.0	—	570.2	380.8	—	362
3	4	568.1	—	567.7	350.2	—	344

Experimental results.