Correlations in fuselage response and sound field in aircraft cabin during flight

The in-flight acoustic field in the aircraft cabin is of fundamental interest to the noise control engineer as it defines the sound quality of the cabin environment which the passenger experiences. Design of efficient noise control treatments is usually based on the spectral characteristics of the interior acoustic field to provide a comfortable environment with a minimum of added weight. In-flight noise diagnostics methods, such as sound intensity mapping, are sensitive to the reverberant nature of the cabin sound field. The performance of active noise control systems is crucially dependent on the statistical characteristics of the enclosed field. However, statistical modeling to characterize the aircraft cabin noise field, e.g., correlation modeling, has received little attention. Apparently, acoustic correlation models used in architectural acoustics have been presumed to represent the in-flight cabin noise field. The statistical description of the aircraft cabin acoustic field can help in understanding and describing the intricate nature of the noise field in greater detail. The main objective of this paper is to discuss correlation models between the exterior pressure field, the vibration response of fuselage panels, and the interior noise field. Test data from ground and flight tests conducted on an MD-90 aircraft are used to examine these correlations.