2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/202923In the limit of low viscosity, we show that the amplitude of the modes of oscillation of a rotating fluid, namely inertial modes, concentrate along an attractor formed by a periodic orbit of characteristics of the underlying hyperbolic Poincaré equation. The dynamics of characteristics is used to elaborate a scenario for the asymptotic behaviour of the eigenmodes and eigenspectrum in the physically relevant régime of very low viscosities which are out of reach numerically. This problem offers a canonical ill-posed Cauchy problem which has applications in other fields.4 pages, 5 figFluid DynamicsAstrophysicsCondensed MatterGeneral Relativity and Quantum CosmologyPattern Formation and Solitonstext