Estimation of the sound in ship cabins considering low frequency and flowing noise characteristics of HVAC duct

Abstract Ducts are inevitable for HVAC systems featuring cabin air supply in naval vessels. Accordingly, the noise characteristics of the duct should be considered in the numerical estimation of acoustic sound in a cabin. This is of particular importance at the low frequency range where the fluid–structure interaction contributes to the vibro-acoustic behavior. This contributes for a difference in the numerical and experimental sound pressure level at the low frequency range. In order to reduce this difference, the sound attenuation level in a duct, sound transmission loss through the duct, and the end reflection factor of the duct end are defined experimentally with ducts used in the naval vessel. In addition, the breakout sound of a duct caused by flowing in a duct is also defined through the experiment. The indoor noise of the typical cabins of the naval vessel is estimated by applying the sound characteristics defined in this research. The sound characteristics are verified by investigating the difference between the estimated and measured sound pressure levels of the typical cabins.