Self-Similar Solutions to the Hele-Shaw Problem with Surface Tension
Siddhant Agrawal, Neel Patel
TL;DR
This work addresses the dynamics of a single-phase Hele-Shaw interface with surface tension in the plane, focusing on interfaces that begin with a corner. The authors develop a conformal-coordinate framework to derive a third-order nonlocal self-similar equation dominated by the Hilbert transform, and they first analyze a linear approximation to understand the asymptotics. Using a weighted functional-analytic setup, they prove existence, decay, and regularity for the linear problem via a δ-regularized variational scheme, then extend to the full nonlinear equation through a contraction mapping for small corner perturbations, yielding a family of self-similar solutions that are smooth for $t>0$. The results provide explicit structural insight into corner dynamics under surface tension and establish a rigorous foundation for self-similar free-boundary behavior in Hele-Shaw-type problems.
Abstract
We consider the Hele-Shaw problem with surface tension in an infinite domain. We prove the existence of a family of self-similar solutions. At $t=0$, these solutions have a corner of angle $θ$ with $ 0 < |θ- π| \ll 1$, and for $t>0$, the solutions are smooth.
