Three-dimensional mathematical problems of interaction between
elastic and scalar oscillation fields are investigated.
An elastic field_is to be defined in a bounded inhomogeneous
anisotropic body occupying the domain $\overline{\Omega_1} \cup \bbR^3$
while_a physical (acoustic) scalar field is to be defined in the exterior domain
$\overline{\Omega_2} = \bbR^3\\ \Omega_1$ which is filled up also by an anisotropic (fluid) medium. These
two fields satisfy the governing equations of steady state oscillations in the
corresponding domains together with special kinematic and dynamic transmission
conditions on the interface $\delta\Omega_1$. The problems are studied by the so-called non-local
approach, which is the coupling of the boundary integral equation method (in
the unbounded domain) and the functional-variational method (in the bounded
domain). The uniqueness and existence theorems are proved and the regularity
of solutions are established with the help of the corresponding Steklov-Poincare
type operators and on the basis of the Garding inequality and the Lax-Milgram
theorem. In particular, it is shown that the physical fluid-solid acoustic
interaction problem is solvable for arbitrary values of the frequency parameter.
Keywords :
fluid-structure interaction, boundary integral method, variational method