Abstract: Particle finite element method (PFEM) is used to incompressible multi-fluid flows include arbitrary numbers of fluids. Identification of internal interfaces is a key. It is solved by subdivision of mixed elements which are divided into single-fluid elements. To adapt to different fluid properties, a stabilized formulation based on finite calculus procedure is used in fractional step method. Boundary point birth, particle velocity control, and automatically penetration check are used for preventing penetration. Accuracy and reliability of PFEM and interface identification measure are demonstrated with Rayleigh-Taylor instability test and collapse of water column. Finally, seven fluids mixing shows that mixing of an arbitrary number of immiscible fluids could be simulated easily.

Key words: particle finite element method(PFEM), multi-fluid flows, incompressible fluids, fractional step method, interface identification