This work reviews present knowledge of double-diffusive convection at low Prandtl number obtained using direct numerical simulations, in both the fingering regime and the oscillatory regime. Particular emphasis is given to modeling the induced turbulent mixing and its impact in various astrophysical applications. The nonlinear saturation of fingering convection at low Prandtl number usually drives small-scale turbulent motions whose transport properties can be predicted reasonably accurately using a simple semi-analytical model. In some instances, large-scale internal gravity waves can be excited by a collective instability and eventually cause layering. The nonlinear saturation of oscillatory double-diffusive convection exhibits much more complex behavior. Weakly stratified systems always spontaneously transition into layered convection associated with very efficient mixing. More strongly stratified systems remain dominated by weak wave turbulence unless they are initialized into a layered state. The eff...

中文翻译：

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低普朗特数下的双扩散对流

这项工作回顾了使用直接数值模拟获得的低普朗特数双扩散对流的现有知识，在指法状态和振荡状态下。特别强调模拟诱导湍流混合及其在各种天体物理应用中的影响。低普朗特数下指法对流的非线性饱和通常会驱动小尺度湍流运动，使用简单的半解析模型可以合理准确地预测其传输特性。在某些情况下，大规模的内部重力波会被集体不稳定性激发并最终导致分层。振荡双扩散对流的非线性饱和表现出更复杂的行为。弱分层系统总是自发地转变为与非常有效的混合相关的分层对流。更强烈的分层系统仍然以弱波湍流为主，除非它们被初始化为分层状态。效果...