Self-Similarity and Universality in Rayleigh-Taylor, Boussinesq Turbulence

TL;DR

This paper investigates the statistical properties of turbulence in Rayleigh-Taylor instability, revealing self-similarity and universality in density and velocity fluctuations within the mixing zone, independent of initial conditions.

Contribution

It presents novel observations of spectral self-similarity and universality in Rayleigh-Taylor turbulence, emphasizing independence from initial interface perturbations.

Findings

Spectral self-similarity of velocity and density fluctuations

Independence of spectra from horizontal slice level

Universality of internal structure regardless of initial perturbations

Abstract

We report and discuss case study simulations of the Rayleigh-Taylor instability in the Boussinesq, incompressible regime developed to turbulence. Our main focus is on a statistical analysis of density and velocity fluctuations inside of the already developed and growing in size mixing zone. Novel observations reported in the manuscript concern self-similarity of the velocity and density fluctuations spectra inside of the mixing zone snapshot, independence of the spectra of the horizontal slice level, and universality showing itself in a virtual independence of the internal structure of the mixing zone, measured in the re-scaled spatial units, of the initial interface perturbations.