Optimal stabilization rate for the wave equation with hyperbolic boundary condition
Hugo Parada, Nicolas Vanspranghe
TL;DR
The paper analyzes energy decay for the wave equation on a bounded domain with a dynamic (hyperbolic) boundary condition and boundary damping. By establishing a robust operator-theoretic framework and performing detailed microlocal analysis of high-frequency quasimodes, it proves that the energy decays at a polynomial rate of $o(t^{-1})$ under geometric control on the dynamic boundary portion and a finite-contact condition. The authors further show sharpness of this rate via a disk example, using a spectral construction inspired by Bessel functions to demonstrate obstructions to faster decay. A decoupling argument and a boundary observability result underpin the resolvent estimates that drive the decay result, providing a comprehensive picture of stabilization limits for dynamic boundary systems. These results illuminate the influence of boundary dynamics and GCC on stabilization performance and guide design considerations for boundary damping in multi-dimensional domains.
Abstract
We show that the energy of classical solutions to the wave equation with hyperbolic boundary condition (i.e., dynamic Wentzell boundary condition) and damping on the boundary decays like 1/t. In fact we allow mixed boundary conditions: a possibly empty, disjoint part of the boundary may be kept at rest provided that the dynamic part satisfies the geometric control condition. We also prove that this decay rate is sharp. Our results follow from resolvent estimates, which we establish by studying high-frequency quasimodes.
