Energy transmission through curved double-wall panel: A numerical approach

Abstract

It is a common practice in aerospace and automobile industries to use double wall panels as fuselage skins or in window panels to improve acoustic insulation. However, the scientific community is yet to develop a reliable prediction method for a suitable vibro-acoustic model for sound transmission through a curved double-wall panel. In this quest, the present work tries to delve into the modeling of energy transmission through a double-wall curved panel and the subsequent radiation of sound power in low to mid frequency range into the free field from the exterior curved panel. A modal expansion theory based on Green’s theorem is implemented to model the energy transmission through an acoustically coupled double-wall curved panel. A method based on the boundary element (BE) technique is then employed to calculate the radiated sound into the free field from the curved panel. The main advantage derived from BEM is that it is sufficient to discretise the radiated surface alone and there is no need to mesh the infinitely extended acoustic domain surrounding the vibrating surface as the non-reflecting boundary condition has been already implemented while developing the governing BEM equation. The developed BEM program is first validated experimentally for a flat panel where it is found to work with reasonable accuracy. The BEM program is also compared for a curved panel numerically with the elemental radiator approach. It has been observed in the present study that the radius of curvature of the surface has a prominent effect on the characteristics of radiated sound power into the free field. Effect of thickness of the air gap between the two curved surfaces on sound power radiation has also been noted.