On Finite Volume Discretization of Infiltration Dynamics in Tumor Growth Models

TL;DR

This paper develops an improved finite volume discretization approach for tumor growth models involving free boundary problems, ensuring conservation laws and accuracy in numerical solutions.

Contribution

It introduces a novel finite volume framework with segregated flux computations that preserve key physical laws and enhances classical methods for better accuracy.

Findings

Enhanced methods preserve incompressibility constraint

Improved accuracy over conventional finite volume methods

Framework applicable to hyperbolic free boundary problems

Abstract

We address numerical challenges in solving hyperbolic free boundary problems described by spherically symmetric conservation laws that arise in the modeling of tumor growth due to immune cell infiltrations. In this work, we normalize the radial coordinate to transform the free boundary problem to a fixed boundary one, and utilize finite volume methods to discretize the resulting equations. We show that the conventional finite volume methods fail to preserve constant solutions and the incompressibility condition, and they typically lead to inaccurate, if not wrong, solutions even for very simple tests. These issues are addressed in a new finite volume framework with segregated flux computations that satisfy sufficient conditions for ensuring the so-called totality conservation law and the geometric conservation law. Classical first-order and second-order finite volume methods are enhanced in this framework. Their performance is assessed by various benchmark tests to show that the enhanced methods are able to preserve the incompressibility constraint and produce much more accurate results than the conventional ones.