# Turbulence generation through an iterative cascade of the elliptical instability

## TL;DR

This paper proposes that the elliptical instability, arising from vortex interactions, acts as a fundamental mechanism driving the turbulent energy cascade across scales, supported by experiments and simulations.

## Contribution

It introduces a mechanistic framework where iterative elliptical instabilities generate the vortex interactions that produce turbulence.

## Key findings

- Elliptical instability leads to secondary and tertiary filament formation.
- Two and three cascade iterations observed in experiments and simulations.
- Elliptical instability may be a key mechanism in turbulence development.

## Abstract

The essence of turbulent flow is the conveyance of energy through the formation, interaction, and destruction of eddies over a wide range of spatial scales--from the largest scales where energy is injected, down to the smallest scales where it is dissipated through viscosity. Currently, there is no mechanistic framework that captures how the interactions of vortices drive this cascade. We show that iterations of the elliptical instability, arising from the interactions between counter-rotating vortices, lead to the emergence of turbulence. We demonstrate how the nonlinear development of the elliptical instability generates an ordered array of antiparallel secondary filaments. The secondary filaments mutually interact, leading to the formation of even smaller tertiary filaments. In experiments and simulations, we observe two and three iterations of this cascade, respectively. Our observations indicate that the elliptical instability could be one of the fundamental mechanisms by which the turbulent cascade develops.