Stability of Lamb dipoles

Abstract

The Lamb dipole is a traveling wave solution to the two-dimensional Euler equations introduced by Chaplygin (Trudy Otd Fiz Nauk Imper Mosk Obshch Lyub Estest 11:11-14, 1903) and Lamb (Hydrodynamics, 1906.) at the early 20th century. We prove the orbital stability of this solution based on a vorticity method initiated by Arnold. Our method is a minimization of a penalized energy with multiple constraints that deduces existence and orbital stability for a family of traveling waves. As a typical case, the orbital stability of the Lamb dipole is deduced by characterizing a set of minimizers as an orbit of the dipole by a uniqueness theorem in the variational setting.