ABSTRACT
Several researchers have reported the detachment of vapor bubbles from a vertical heated wall in upward flow boiling of water. In these experiments, the bubble shape was frequently flattened along the wall at inception but became more rounded before the onset of detachment. In this study, the motion of two-dimensional bubbles is investigated numerically to elucidate the mechanism of bubble detachment. The numerical results show that the change in bubble shape due to surface tension force induces the liquid flow from the periphery to the base of bubble and consequently the liquid inertia lifts the bubble from the wall.