Advanced computational techniques, such as Delayed Detached Eddy Simulation (DDES) and Large Eddy Simulation (LES) methods, have demonstrated the complex unsteady aerodynamics associated with S-duct intakes, but they are still too computationally expensive. The promising substitute Lattice-Boltzmann Method (LBM) was selected in this project. The commercial solver XFlow was used to perform the simulation of an S-duct intake operating in the incompressible regime, with an inlet Mach of 0.27. The impact of sub-grid scale modeling and lattice structure on LB unsteady flow distortion predictions at the S-duct aerodynamic interface plane has been addressed. A validation against Particle Image Velocimetry (PIV) measurement has been then conducted.