Numerical study of the high-intensity heat conduction effect on turbulence induced by the ablative Rayleigh–Taylor instability

Abstract

By adopting heat conduction of the Spitzer form in implicit large eddy simulations, the effect of high-intensity heat conduction on turbulence induced by the ablative Rayleigh–Taylor instability is studied in this paper. The height of the spike and bubble exhibit self-similar evolution with t2 dependence by the late stage of simulations, while heat conduction suppresses the coefficient of spike αs and slightly enhances that of the bubble αb. Heat conduction displays a strong damping effect for small-scale fluctuations of the temperature and density field, resulting in a much steeper slope for energy spectra in intermediate scales. The diffusion effect is responsible for the suppression of temperature fluctuations, and velocity dilatation is shown to be a possible route for heat conduction to affect density fluctuations. The impact of heat conduction on the velocity field is relatively weak, with vertical velocity spectra exhibiting classical Kolmogorov inertial range in intermediate scales. By comparing enstrophy profiles, it is found that vorticity tends to peak at the bubble side in cases with high-intensity heat conduction.