Fluid-structure coupled response of dynamical surfaces tailored in a flexible shell

The present study examines the fluid-coupled wave response of a stepped elastic membrane discontinuity connecting a flexible shell to the annular rigid shell. The acoustic radiation from the internal and annular regions propagates along the flexible boundaries as well as through the compressible fluid that fills the interior of the shell and scatters at geometric discontinuity and edges. In contrast to previous studies, an elastic membrane disc with different boundary conditions is considered as the geometric discontinuity rather than an acoustically rigid step-discontinuity in a cylindrical waveguide. The problem governed by the rigid step-discontinuity is solved using the mode matching technique, while the Galerkin procedure is used for the elastic membrane discontinuity. The truncated form of both solutions reconstructs the matching conditions and satisfies the conservation laws, which further authenticate the correctness of the solutions and the validity of the obtained numerical results based on these solutions. It is worth noting that the parametric configuration of the elastic membranes, the edge conditions and the radii of the shells have a significant impact on the attenuation of the noise control device.