Abstract: Based on the incompressible smoothed particle hydrodynamics(ISPH) method, one constraint moving boundary problem in screw extrusion has been investigated, and the program is written in FORTRAN. The dummy particles are used to treat the moving boundary. A fixed boundary model is also simulated. The tensile instability is avoided by setting a reference pressure. Through comparing the results separately produced by the moving boundary model, the fixed boundary model and the commercial software FLUENT, it has been shown that the boundary treatment method is simple and effective, the algorithm is accurate and fast if an appropriate resolution is selected and the high order derivable kernel function could give a better result. It laid the foundation for the simulating of the more complex 3D model. It has something referential value for the research on moving boundary problems in various areas.

Key words: Dummy boundary particles, Incompressible flow, Incompressible smoothed particle hydrodynamics, Moving boundary