Acoustic receptivity of distributed micron-sized roughness elements is investigated for a swept-wing boundary layer by means of direct numerical simulations (DNS) and parabolised stability equations (PSE) computations. The geometry and flow configuration follow the experiments by [4] and DNS calculations by [7]. Acoustic wave has been modeled by superposing a periodic fluctuation εcos(ωt) to the inflow streamwise velocity component. A range of amplitudes and frequencies are considered to perform simulations and to study acoustic wave-roughness elements interaction.