On the initial stage of the evolution of hydrodynamic parameters during deep penetration of metals by high-power laser radiation

A qualitative analysis of changes in hydrodynamic parameters during keyhole formation by thermocapillary melt removal under the point action CW laser radiation is presented. It established that rapid surface deformation leads to adhesion viscous sublayer melting boundary and creation shear structure flow which stimulates acceleration growth. Keywords: formation, radiation, effect, flow, sublayer, sticking.