High resolution numerical study of Rayleigh-Taylor turbulence using a thermal lattice Boltzmann scheme

Abstract

We present results of a high resolution numerical study of two dimensional (2d) Rayleigh-Taylor turbulence using a recently proposed thermal lattice Boltzmann method (LBT). The goal of our study is both methodological and physical. We assess merits and limitations concerning small- and large-scale resolution/accuracy of the adopted integration scheme. We discuss quantitatively the requirements needed to keep the method stable and precise enough to simulate stratified and unstratified flows driven by thermal active fluctuations at high Rayleigh and high Reynolds numbers. We present data with spatial resolution up to 4096 x 10000 grid points and Rayleigh number up to Ra ~ 10^11 . The statistical quality of the data allows us to investigate velocity and temperature fluctuations, scale-by-scale, over roughly four decades. We present a detailed quantitative analysis of scaling laws in the viscous, inertial and integral range, supporting the existence of a Bolgiano-like inertial scaling, as expected in 2d systems. We also discuss the presence of small/large intermittent deviation to the scaling of velocity/temperature fluctuations and the Rayleigh dependency of gradients flatness.

31 pages, 21 figures

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• Evolution of a double-front Rayleigh-Taylor system using a GPU-based high resolution thermal Lattice-Boltzmann model
• Immiscible Rayleigh-Taylor turbulence using mesoscopic lattice Boltzmann algorithms
• Numerical simulations of compressible Rayleigh-Taylor turbulence in stratified fluids
• Validation and application of the lattice Boltzmann algorithm for a turbulent immiscible Rayleigh-Taylor system
• A numerical tool for the study of the hydrodynamic recovery of the Lattice Boltzmann Method
• Lattice QCD Applications on QPACE
• Performance evaluation of high-order reconstruction for discrete unified gas-kinetics scheme in tracking fluid interfaces
• Second order closure for stratified convection: bulk region and overshooting