The purpose of this paper is to study the effect of a porous, compliant, anisotropic coating on the fluid-dynamical performance of a NACA0012 airfoil, under conditions of boundary-layer separation. This fluid-structure interaction problem is studied computationally in two dimensions by performing a detailed parametric study of the coating, with respect to its physical dimensions, characteristics and placement on the airfoil. Aerodynamic performances are quantified in terms of the non-dimensional mean drag and lift coefficients. The configuration described here is a separated flow at Re = 1100 and
= 70°. Coating parameters are found which decrease the amplitude of the drag oscillations by about 11% and increase the mean lift by about 9%.