A theoretical model of thermocapillary flows in laser welding

Surface tension variations on the surface of the weld pool produced by a laser during the process of welding, can produce very strong currents. A linearized description of the process is constructed, as well as a non-linear boundary layer model that takes account of thermal conduction and fluid convection. It is found that there is a considerable difference between the predictions of the two approaches. The non-linear model produces results that are compatible with what is believed to occur in practice.