Asymptotically self-similar graph-like solutions to a multi-dimensional surface diffusion flow equation under contact angle and no-flux boundary conditions
Yoshikazu Giga, Sho Katayama
TL;DR
The paper studies Mullins' model of a surface diffusion flow in a multidimensional half-space with a contact-angle boundary condition and a no-flux boundary, focusing on graph-like initial surfaces. By reformulating the problem as a quasilinear parabolic equation and solving it via integral equations built from layer- and volume-potentials for an anisotropic biharmonic operator, the authors develop a framework in scaled Hölder spaces $Z_\alpha^{k+\mu}$ to handle long-time behavior and boundary effects. They establish global existence for small perturbations of a base slope $\gamma_0=\tan\theta$, construct self-similar solutions for homogeneous data, and prove convergence to self-similar profiles for asymptotically homogeneous initial data, without requiring a small-angle restriction. The results extend prior one-dimensional works to higher dimensions and provide a robust nonlinear-analytic approach using contraction mappings and Schauder-type estimates, yielding a family of self-similar solutions dictated by boundary data with potential impact on thermal grooving and related geometric diffusion phenomena.
Abstract
This paper studies Mullins' model of thermal grooving which consists of a surface diffusion flow equation with contact angle and no-flux boundary conditions. We consider this problem in a multi-dimensional half space and prove that if the slope of the initial data is close to that consistent with the contact angle, then there exists a unique global-in-time solution. In particular, we show the existence of a self-similar solution for a given behavior at the space infinity. We also show that our global solution converges to a self-similar solution as the time tends to infinity if the initial data is asymptotically homogeneous at the space infinity. No assumption on the size of the contact angle is imposed.
