The Cauchy problem for nonlinear dispersive models of long internal waves in the presence of the Coriolis force
Ricardo Freire, Thyago S. R. Santos
TL;DR
The paper analyzes nonlinear, nonlocal dispersive models for long internal waves in a rotating frame, focusing on the Rotational Modified Benjamin-Ono and Rotational Modified ILW equations with a Coriolis term $\gamma\partial_x^{-1}u$. It develops an unconditional well-posedness theory in the low-regularity spaces $Z^s_x(\mathbb{R})$ for $s>\tfrac12$ using a dyadic, energy-based method inspired by Molinet–Vento, and establishes global well-posedness for $s\ge 1$ via conserved quantities. An ill-posedness result rules out $C^2$-smooth data-to-solution maps in these spaces, highlighting the delicate balance between nonlocal dispersion and rotation. The analysis employs Bourgain spaces $X^{s,b}$, a detailed Littlewood–Paley decomposition, and pseudoproduct techniques to control resonant interactions, with extensions to the ILW class through the Dirichlet-to-Neumann type operator $\mathcal{T}_\delta$ and discussion of the deep-water limit. The results illuminate how Coriolis effects interact with nonlocal dispersion in a rigorous well-posedness framework and lay groundwork for broader dispersion perturbations $D^\alpha_x$ and related rotating-fluid models.
Abstract
We investigate models of dispersive long internal waves with rotational effects, specifically the Benjamin-Ono (BO) and intermediate long wave (ILW) equations modified by the presence of the nonlocal operator $\partial_x^{-1}$, which mathematically accounts for rotational influences. We establish a local and global well-posedness theory while ensuring the unconditional uniqueness of solutions in low-regularity Sobolev-type spaces. Our approach is based on techniques introduced by Molinet and Vento in \cite{MR3397003}.
