Figure 1.

Schematic showing the geometry of the model domain. The skull is located at x = 0, and x = G(t) represents the boundary of a growing tumor, which is assumed to occupy the region G(t) < x < L, shown in red. The tumor-tissue interface is assumed to move into healthy tissue with a fixed velocity v that is representative of tumor growth. This boundary is permeable to fluid but impermeable to healthy tissue, and the skull is impermeable to both tissue and fluid. To see this figure in color, go online.