Low Rossby limiting dynamics for stably stratified flow with Finite Froude number

TL;DR

This paper derives reduced equations for slow dynamics in rotating stratified flows at finite Froude number, revealing decoupled horizontal and vertical kinetic energy dynamics, supported by numerical simulations showing Taylor-Proudman column formation.

Contribution

It introduces new reduced equations capturing the slow dynamics of rotating stratified flows, highlighting a decoupling of horizontal and vertical kinetic energy.

Findings

Spontaneous formation of Taylor-Proudman columns observed in simulations.

Decoupling of horizontal kinetic energy from vertical buoyancy dynamics.

Validation of theoretical reduced equations with high-resolution simulations.

Abstract

In this paper we explore the fast rotation, nonhydrostatic limit of the rotating and stratified Boussinesq equations. We derive new reduced equations for the slow dynamics that describe Taylor-Proudman flows. One new aspect of the dynamics is a decoupling of the horizontal kinetic energy, described by 2D Navier-Stokes, from new dynamics that describe the coupling of vertical kinetic energy and buoyancy. We support the theory with high resolution numerical simulations of the full Boussinesq equations that, in this limit, reveal the spontaneous formation of Taylor-Proudman columns and their dynamics.