Predicting and understanding vortical flows around a fighter aircraft is crucial to be able to carry out agile maneuvers at high angles of attack and side slip. Two prototypes of model military aircraft are studied with various multi swept wing configurations and PIV measurements are carried out by Airbus Defence and Space and the Technical University of Munich. Computations are performed with the in-house viscous-flow solver ISIS-CFD (aka FINE/Marine). This code solves the incompressible flow using unstructured grids and finite volume discretisation. In this study, two turbulence models are used: the k-omega SST model and an hybrid RANS/LES model (DDES-SST). Moreover, the role played by the discretisation error is assessed by using anisotropic automatic grid refinement procedures based on flow-related criteria developed for both statistic and hybrid RANS/LES turbulence closures.