Project. Media covered by compliant solid structures permeated by viscous fluids are ubiquitous in nature and increasingly seen in technology. Deformations of such a composite and the effects they induce on the surrounding fluid flow have lately been regarded as accounting for a variety of phenomena by biologists, physicists and engineers. This research project aims to evaluate the effects of these kinds of coatings on the onset of instabilities in laminar flow and their capabilities to reduce the skin friction under both transitional and turbulent flow conditions. Research activity carried on so far has brought to the implementation of a finite difference DNS code of a 2D viscous flow around deformable bodies. Classical Navier-Stokes equatons are solved on a staggered cartesian grid using the Fractional Step Method, whereas solid stresses are computed by taking the variational derivative of the body's energy function. Finally, the fluid-structure interaction is handled by means of the Immersed Boundary Method.