A free-front tracking algorithm for a control-volume-based Hele-Shaw method

With free surface ßow problems the position of the free front at a particular time step needs to be predicted. When simulating the ßow of hot molten polymer in injection moulds this position is essential for the prediction of the position of the weld lines on the Þnal product. Weld lines are important in that they indicate positions of diminished strength and spoil the aesthetics of the product. A code using a Þnite volume approach on the thin gap HeleÐShaw ßow equations to simulate the Þlling stage of the injection moulding process has been developed which requires a suitable algorithm for the free-front tracking. The Volume of Fluid (VOF) method was implemented in this study for the tracking of the free front. The discretization and various formulations of the VOF equation are presented as well as the results obtained. The impact on the existing equations is also investigated as well as the development of a packing routine that is used to eliminate the di¤usive nature of the VOF equation