Nonsymmetric traveling wave solution to a Hele-Shaw type tumor growth model
Yu Feng, Qingyou He, Jian-Guo Liu, Zhennan Zhou
TL;DR
This work studies boundary instabilities in a PME-derived Hele-Shaw tumor growth model by rigorously establishing the existence of nonsymmetric traveling wave solutions in a two-dimensional tube. The authors formulate a nonlinear map $F(\xi,\lambda)$ whose trivial branch corresponds to symmetric traveling waves and whose nontrivial zeros yield traveling-wave boundaries with shape $\xi(y)$ near $\varepsilon\cos(ly)$. Central to the analysis is the Fréchet derivative $F_\xi(0,\lambda)$, which reduces to an eigenvalue problem with eigenfunctions $\cos(ly)$ and eigenvalues $E(\lambda,l)$; zeros of $E(\lambda,l)$ pinpoint bifurcation points $\lambda_0^l$, enabling Crandall–Rabinowitz bifurcation to generate branches of nonsymmetric solutions. The main result shows that for each perturbation frequency $l\in\mathbb{N}$ there exists a local bifurcation branch $(\xi_{\varepsilon},\lambda_{\varepsilon})$ emanating from $(0,\lambda_0^l)$, confirming intrinsic boundary instability in the PME-derived Hele-Shaw tumor model. This provides a rigorous framework linking boundary morphology to nutrient consumption and supports the formation of finger-like protrusions in tumor growth scenarios.
Abstract
We consider a Hele-Shaw model that describes tumor growth subject to nutrient supply. The model is derived by taking the incompressible limit of porous medium type equations, and the boundary instability of this model was recently studied in \cite{feng2022tumor} using asymptotic analysis. In this paper, we further prove the existence of nonsymmetric traveling wave solutions to the model in a two dimensional tube-like domain, which reflect intrinsic boundary instability in tumor growth dynamics.
