Research Article
Sound Radiation Characteristics of a Rectangular Duct with Flexible Walls
Table 4
(a) Coupled modes of a rectangular duct. (b) Comparison of uncoupled and coupled modes of a rectangular duct.
(a) |
| Mode number | Frequency (Hz) | Mode number | Frequency (Hz) | Mode number | Frequency (Hz) |
| 1 | 100.48 | 11 | 208.23 | 21 | 282.82 | 2 | 105.36 | 12 | 219.39 | 22 | 294.39 | 3 | 121.47 | 13 | 226.30 | 23 | 301.62 | 4 | 126.61 | 14 | 232.59 | 24 | 311.92 | 5 | 140.08 | 15 | 238.81 | 25 | 343.82 | 6 | 141.47 | 16 | 254.16 | 26 | 347.07 | 7 | 162.99 | 17 | 258.02 | 27 | 352.22 | 8 | 177.12 | 18 | 260.92 | 28 | 361.28 | 9 | 189.14 | 19 | 266.91 | 29 | 367.71 | 10 | 195.22 | 20 | 282.74 | 30 | 374.89 |
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(b) |
| Uncoupled mode frequency (Hz) | Mode type | Coupled mode frequency (Hz) |
| 99.22 | Structural | 100.48 | 113.3 | Acoustic | 105.36 | 114.59 | Structural | 121.47 | 127.08 | Structural | 126.61 | 140.51 | Structural | 140.08 | 141.94 | Structural | 141.47 | 163.47 | Structural | 162.99 | 177.17 | Structural | 177.12 | 189.68 | Structural | 189.14 | 195.60 | Structural | 195.22 | 208.72 | Structural | 208.23 | 224.69 | Structural | 219.39 | 226.6 | Acoustic | 226.30 | 345.1 | Structural | 343.82 | 345 | Acoustic | 347.07 |
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