This chapter details four numerical schemes to deal with the coupling between the three forces. The steady and unsteady normal-wash, which is the Neuman’s boundary condition of the potential flow problem with the effect of structural deformation, is explained. Then, the transformation matrices between translational and rotational displacements of an aerodynamic grid and those of a finite element grid are presented. The estimation of generalised aerodynamic force (GAF) matrices so as to decouple the velocity and frequency of the unsteady aerodynamic model is detailed. The last section deals with a mode tracking technique used for flutter analysis.