Sound-Structure Interaction Fundamentals

This chapter demonstrates what structural vibrations do to neighboring acoustic fluids, and what sound fields do to neighboring structures. The overarching concept of linear sound-structure interaction is simple: the normal particle velocity in the structure and fluid along the fluid-structure interaction boundary must be the same. This means that when a structure vibrates against a fluid, the component of the vibration normal to the structural surface must be identical to the corresponding particle velocity in the neighboring fluid. The chapter starts by examining how a structure's vibrations compress and expand a neighboring fluid. Next, it shows how two important structures, a circular baffled piston and a flat rectangular flexible finite plate, eradiate sound, and are fluid-loaded by the impedance of the surrounding acoustic fluid. Finally, the chapter considers the complementary problem of how acoustic waves induce vibration in a structure.