Abstract
The phase changing problem at the liquid-solid interface that occurs during stationary gas tungsten arc (GTA) welding has been studied by considering the four driving forces for weld pool convection, that is the electromagnetic force, the buoyancy force, the aerodynamic drag force and the surface tension force at the weld pool surface. In the numerical simulation, difficulties associated with the irregular shape of the moving interface have been successfully overcome by adopting a boundary-fitted coordinate system that eliminates the analytical complexity at the liquid-solid boundary. This method also has the capacity to handle the time-dependent changing solution domain of the moving boundary problem and could be applied effectively to this transient weld pool development problem with the moving boundary and phase change condition.