A numerical method based on unstructured grids was proposed to simulate ice accretions on multi-element airfoils. The air flowfield was solved using the Euler equations. Based on air velocity distribution

the governing equations for droplets were solved using an iterative method to obtain the collection efficiency. The different freezing models corresponding to the rime and glaze ice were employed to simulate the freezing process. The process of ice accretions was simulated with the assumption that ice accumulates layer-by-layer

and the ice shape was built with the assumption that ice grows in the direction normal to the airfoil surface. The rime and glaze ice accretions on a typical three-element airfoil were investigated. According to the flowfield around the airfoil

a method of computing the freezing model for glaze ice was presented. The effects of ice accretions on performance of the multi-element airfoil were also analyzed.