Junctions areas, for instance at the wing-fuselage junction, are of utmost importance on aircraft. However, the aerodynamics of such intersection regions still remains unclear and challenging to predict, both experimentally and numerically. Therefore, this study aimed at identifying and analysing the origins and properties of the phenomena involved within junctions so as to investigate the onset of corner separations. The preliminary literature review allowed the assumption of preferred conditions for the existence of corner separations. Thus, dedicated configurations were set up in order to investigate these conditions in wind tunnel and by CFD. The thorough analysis of a first test case highlighted the global dynamics of the horseshoe vortex. The well known bimodal behaviour as well as cross flow oscillations - so-called meandering - have been characterised thanks to the Large Eddy Simulation approach. The high level of turbulence anisotropy in the corner area is supposed to be the main reason of the bad results obtained with statistical models during this study. Eventually, the sensitivity study of the first test case showed that the corner separation is likely to be triggered by increasing the aerodynamic load on the junction. This work emphasizes the need to improve the knowledge of corner separations physics in order to be able to predict them accurately. This will not be achieved without the creation of junction-flows-dedicated databases, which are still lacking.