Fluid simulations in large domains with few complex regions of interest do not require full 3D simulations, but we can instead partition the domain and only simulate regions of interest with 3D models, while simulating the rest with 1D models. preCICE has already been used for 1D-3D FSI simulations of helicopter rotor blades, as well as 2D-3D flow simulations. In this thesis, we are using preCICE for geometric multi-scale flow-flow-structure simulations. We focus on coupling 1D and 3D flow simulations of elastic tubes, comparing different scenarios.