The aim of the work is to elaborate some consideration on the ejecta particle flows, generated at high velocity impact of an aluminum projectile on thin aluminum targets
at velocities about 3 km/s. Modelling of the ejecta was performed in course of experiments in which a drop of water impacted water surface. The method was motivated not only by the high cost of high velocity impact experiments and obvious difficulties of in-situ registration of the studying phenomena but also by the similarity of ejecta phenomena in water and in aluminum.