4. Two- and three-dimensional models

Some parts have globally three-dimensional geometries that are difficult to represent with a thin layer. What's more, most parts exhibit locally complex flow patterns, such as in thresholds at the junction with the cavity, at the level of ribs, or at the material front. Obtaining an average surface to apply the Hele-Shaw equations is therefore difficult, and the approximations used are questionable.

It is then necessary to directly solve the dynamic equilibrium equations (2) associated with the behavior law