In the spectrum of carbone dioxyde (CO2) reduction, new configurations of turbofans are designed. The openrotor is expected to achieve a reduction of 20% of emissions compared to current configurations. Nonetheless, it presents many challenges such as the influence of the boundary layer transition on the performances. This study aims to propose a methodology to analyse the boundary layer transition on an openrotor with Large Eddy Simulation (LES). A monogrid study is proposed. Some methodological challenges are covered, related to the mesh generation to avoid numerical instabilities. Limitations for the use of the 2.5D hypothesis are shown, leading to an axisymmetric simulation of a stator between two streamsurfaces. The results of this configuration are discussed in light of boundary layer transition.