Post-processing of two-phase DNS simulations exploiting geometrical features and topological invariants to extract flow statistics: application to canonical objects and the collision of two droplets

International audience ; This work presents a methodology to collect useful flow statistics over DNS simulations exploiting geometrical properties maps and topological invariants. The procedure is based on estimating curvatures on triangulated surfaces as as averaged values around a given point and its first neighbours (the 1-ring of such a point). In the case of two-phase flow high-fidelity simulations, the surfaces are obtained after an iso-contouring procedure of the volumetric level-set field. The estimation of the curvatures on the surface allows the possibility of characterizing the 3D objects that are created in a high-fidelity simulation in terms of their area-weighted geometrical maps. In this work we provide an assessment of the robustness of the curvature estimation algorithm applied to some canonical 3D objects and to the Direct Numerical Simulation of the collision of two droplets. We provide the tracking of the topological evolution of such objects in terms of geometrical maps and we highlight the effect of mesh resolution on those topological changes.