Abstract. Volume Of Fluid (VOF) is one of the most powerful methods to resolve free surface ows. In this study, a new algorithm is developed in a curvilinear coordinate system, which implements an implicit pressure based method (SIMPLE) with a staggered grid and a Lagrangian propagation of the interface, using the VOF method in the computational domain. Based on this algorithm, a computer code is generated and two test cases of dam-breaking problems, both in curvilinear and Cartesian grid systems, are examined and, then, two applications of this method, including ow through a curved gate under a dam and the impact problem of a circular cylinder, are presented. The results show good agreement with experimental and other computational results. Keywords: Free-surface; Volume-of- uid; Front tracking; Curvilinear coordinate system; Dambreaking