This work explore the possibility to determine the spray characteristics at early stage of theatomization process. This approach has been firstly proposed in [7] propose to characterizethe liquid-gas surface in term of surface curvature distribution allowing the determination ofwhich part of the surface is already representative of the final spray. This innovative approachis based on numerical simulation but could be extended in principle on experimental imagerytechniques for instance. In this work, the methodology is extended to include surface velocitymeasurements to provide the joint distribution of the spray in term of diameter and velocity. Theconfiguration is representative of an aeronautic injector used in the European project CHAiR-LIFT and focus on the prefilming airblast atomization. Such an atomization process involvesa wide range of length scales. The diameter of the aeronautic atomizer could be three ordersof magnitude higher than the diameter of the smallest droplet. Therefore, performing a CFDsimulation is neither a straightforward nor a cheap process computationally speaking. Thus,a workflow, which divides the atomizer in less complex processes, is presented in this workto make the simulation affordable in an industrial perspective. The objective is to computethe properties that determine the spray behavior for the following combustion process. TheOpenFOAM library is used to perform the simulation. In addition to the numerical strategy tocapture first steps of the atomization process the focus of our presentation will be on the postprocessing of the simulation to extract the main features of the spray. The results presentedconcern the drop size distribution of the spray and the joint velocity distributions of the droplets.The post processing methodology is based on an analysis of the surface density joint distribu-tion for curvatures and velocity. We believe this methodology can be used to enrich the sprayinjection models for further reactive spray flame simulations.