On thermally-driven movement of drops in microgravity conditions

The equations of motion of a liquid drop embedded in a nonmiscible liquid under microgravity conditions were analyzed. A temperature gradient imposed on the outer liquid induces a gradient of surface tension on the surface of the drop. The resulting stresses set the drop in motion. The flow and temperature fields are calculated as expansions for small Marangoni number (analogous to a Reynolds number). The zero order solution yields the velocity of the drop. The deformation is of order 2. It is obtained by solving first the velocity field to order 1.