Fig 1. Schematics of the domain of analysis: the discretised tissue domain and the vascular network.

Schematics of the domain of analysis: the discretised tissue domain and the vascular network. A: Schematic representation of the tumour–host domain, from inside out: solid-tumour (Ω^T) and healthy tissue (Ω^H) containing a network of capillaries. B: Graphical illustration of a representative grid of tissue elements (shown here using two-dimensional finite elements) with the one-dimensional grid of the vascular tree projected on top. Black squares represent the tissue element nodes, and hollow black circles the vascular element nodes. The hollow green diamonds represent vascular network end-points (i.e. tip ECs). C: An overlay of the two meshes, showing the tip and functional vascular-node density, ρ_t and ρ_v, respectively. Note that the finite element mesh of the tissue domain is non-conforming to the corresponding finite element mesh of the vascular network (see also S1 Fig).