Vertical axis wind turbines VAWTs have been demonstrated to possibly be more efficient than traditional turbines, especially in wind farms, where the wake-turbine interaction is intensive. Tools to analyse VAWTs are still studied and improved, especially analytical wake models which are widely used by companies when studying wind farm layouts thanks to the low computational cost. Nevertheless, they are often based on neglecting relevant aspects and incorrect assumptions and derivation, being most of the times horizontal axis wind turbines HAWTs wake models simply transposed to VAWTs. Therefore they are considered inaccurate. The purpose of this thesis is to investigate such methods, defining their validity range and their limitations, shedding light on possible improvements and corrections.