An engineering-type analysis is proposed and used to investigate the performances of thrust vectoring by fluidic injection in the divergent of a supersonic axisymmetrical convergent-divergent nozzle. This method includes several approaches which consist mainly of a fluidic obstacle height evaluation and the prediction of the separation line that results upstream of the fluidic obstacle. The construction of the separation line is also based on some separation correlations proposed in the literature. The nozzle thrust deviation is then calculated by taking into account the injectant fluid momentum rate contribution and the integration of the pressure acting on the nozzle inner wall. The sensitivity of the model versus some separation criteria is discussed. The results of the analytical model are compared with the experiments conducted recently by the authors. The comparison shows a very good agreement for some of the separation criteria over the whole range of injected to main flow-rate ratios.