Three-dimensional numerical simulation of turbulent mixing by Rayleigh–Taylor instability

Abstract

Three-dimensional simulation of the mixing of miscible fluids by Rayleigh–Taylor instability is described for density ratios, ρ1/ρ2, in the range 1.5 to 20. Significant dissipation of density fluctuations and kinetic energy occurs via the cascade to high wave numbers. Comparison is made with experimental measurements of the overall growth of the mixing zone and of the magnitude of density fluctuations. The differences between 2-D and 3-D simulation are discussed.