Direct Numerical Simulation of structural vacillation in the transition to geostrophic turbulence

TL;DR

This paper uses Direct Numerical Simulation to investigate the onset of small-scale fluctuations, known as Structural Vacillation, in a rotating baroclinic annulus, shedding light on the transition to geostrophic turbulence.

Contribution

It provides a detailed numerical analysis of the transition process, linking experimental observations with simulation data to understand flow regime changes.

Findings

Identification of flow regimes leading to vacillation

Characterization of small-scale fluctuation onset

Insights into transition to geostrophic turbulence

Abstract

The onset of small-scale fluctuations around a steady convection pattern in a rotating baroclinic annulus filled with air is investigated using Direct Numerical Simulation. In previous laboratory experiments of baroclinic waves, such fluctuations have been associated with a flow regime termed Structural Vacillation which is regarded as the first step in the transition to fully-developed geostrophic turbulence.