This chapter deals with the discretisation of the LES models of the Navier-Stokes equations (7.1) $$ \begin{gathered} w_t - \nabla \cdot ((2\nu + \nu _T ) \mathbb{D} (w)) + (w \cdot \nabla ) w \hfill \\ + \nabla r + \nabla \cdot \frac{{\delta ^2 }} {{2\gamma }}(A(\nabla w\nabla w^T )) = f in (0, T] \times \Omega , \hfill \\ \nabla \cdot w = 0 in [0, T] \times \Omega , \hfill \\ w (0, \cdot ) = w_0 in \Omega , \hfill \\ \end{gathered} $$ where A is given by the approximation of the Fourier transform of the Gaussian filter, v T is the turbulent viscosity and to simplify the notations we use f instead of $$ \bar f $$ . System (7.1) has to be completed with boundary conditions. Depending on the boundary conditions, the additive constant of the pressure has to be fixed, see Section 5.3.