Thermocapillary motion of bubbles in a melt on exposure of porous metals to laser radiation

An analysis is made of the steady-state thermocapillary motion of a spherical gas bubble in a metal melt with high Reynolds and Marangoni numbers under conditions corresponding to laser melting. Heat exchange at the bubble surface is taken into account. Expressions are derived to describe the thermocapillary drift velocity as a function of the Marangoni number and heat exchange rate.