On the steady motion of a coupled system solid-liquid

The authors study the unconstrained (free) motion of an elastic solid $\mathcal B$ in a Navier-Stokes liquid $\mathcal L$ occupying the whole space outside $\mathcal B$, under the assumption that a constant body force $\mathfrak b$ is acting on $\mathcal B$. More specifically, the authors are interested in the steady motion of the coupled system $\{\mathcal B,\mathcal L\}$, which means that there exists a frame with respect to which the relevant governing equations possess a time-independent solution. The authors prove the existence of such a frame, provided some smallness restrictions are imposed on the physical parameters, and the reference configuration of $\mathcal B$ satisfies suitable geometric properties