|Abstract:|| The interaction between fluid flows and non-smooth surfaces is common in Nature and it is strictly related to phenomena like drag reduction/increase or superhydrophobicity. Microstructured surfaces can modify significantly the motion of a fluid in contact with a body, and a model to include the separation of scales between the micro-features at the surface and the characteristic scale of the macroscopic flow has been developed with a homogenization technique. Homogenization allows to describe the physics both in a microscopic representative volume and in the macroscopic fluid-solid mixture, with a coupling between the two expressed through a
permeability tensor, an effective elasticity tensor, etc.
The technique is used together with a study of the interface conditions needed to match the solutions at the boundary between the pure-fluid and the poroelastic regions. Different models have been introduced both from microscopic and macroscopic points of view, for different flow's regimes,different configurations of the flow and different types of poroelastic structures, comparing the results - when possible - with experiments or direct numerical simulations which take into account fully the topology of the porous or poroelastic matrix.