We present in this paper two Euler/Navier-Stokes couplings for multiscale aeroacoustic problems based on a Discontinuous Galerkin method: the first coupling concerns an interface coupling between adjacent domains, the second coupling concerns a coupling in volume and interface between overlapping domains. In both cases, each domain provide a donor field to the other domain. After a numerical study of the convergence of the precision of the method, these couplings are compared on a 2D test case of a flow around a cylinder and the noise generated.