This paper presents and illustrates the coupling techniques developed at the Laboratoire de Mecanique des Structures, adapted to the analysis of fluid structure coupled behaviours in turbomachines. Three different aspects are considered: the added mass effect, the aeroelastic instability called flutter and the global analysis of flexible wheel-shaft assemblies. These problems are quite different but the coupling techniques used for each case are close. Within this context, the interest of model techniques in particularly highlighted.