English

Variational Instability for Irrotational Water Waves in Finite Depth

Analysis of PDEs 2025-02-25 v1

Abstract

We prove variational instability for small-amplitude solutions to the periodic irrotational gravity water wave problem in finite depth. Our results are based on a reformation of the water wave problem as a pseudo-differential Euler-Lagrange equation together with the local existence theory of small-amplitude waves. We use a perturbative spectral analysis of the second-variation operator in combination with a Plotnikov transformation to show instability for non-trivial solutions.

Keywords

Cite

@article{arxiv.2502.16698,
  title  = {Variational Instability for Irrotational Water Waves in Finite Depth},
  author = {Florian Kogelbauer},
  journal= {arXiv preprint arXiv:2502.16698},
  year   = {2025}
}
R2 v1 2026-06-28T21:54:46.043Z