| 摘要 |
<p>The device has an acoustic grid (6) positioned in a segment of a conduit, where the grid has a length (L1) along an axis of the segment and square meshes (9). Each mesh fits into a square with side (m) so as to satisfy following relationship L1 greater than 1.8 lambda fmin and mless than lambda fmax/2, where fmax and fmin are maximum and minimum frequencies of the noise to be attenuated and lambda fmax and lambda fmin are wavelengths of the noise at maximum and minimum frequencies. The grid has a central opening whose transverse dimension is smaller than 0.75 times inner diameter (D) of the conduit. The segment is made up of metal or composite web.</p> |
