To get rid of all numerical aspects in flow simulation results and to have more informations about the evolution of the physical values inside the computational domain, we have developed a controlling and analysing method of these results. This method is based on the physical conservation laws. The balances are computed on the external surfaces of the computational domain and on a liquid surface moving along the main flow direction. The use of this method is iliustrated in the case of an Euler code. This method allowed us to correct this Euler code and to define a domain of validity for the numerical results obtained.