Diapycnal (irreversible) mixing is analyzed using thirty direct numerical simulations (at \(1024^3\) resolution) of homogeneous rotating stratified turbulence (RST) in the absence of imposed shear or forcing. The influence of varied rotation and stratification rates on the energetics (in particular the dissipation rates of kinetic and potential energies) is presented. Data is also analyzed within a new parametric framework, using the turbulent Froude and Rossby numbers \(Fr_t = \epsilon /Nk\), \(Ro_t = \epsilon / f k\), where k is the turbulent kinetic energy, \(\epsilon\) its rate of dissipation, N the buoyancy frequency and f the Coriolis parameter. This framework is used to illustrate relative magnitudes of the stratification and rotation in geophysical flows and provide a useful tool for explicating the relationship between \(Fr_t\) and \(Ro_t\) as relevant dynamic parameters in the geophysical setting. Results indicate that unforced rotation does not impact the magnitude of the irreversible mixing coefficient (\(\Gamma =\epsilon _P/\epsilon\)) when compared to results without rotation, where \(\epsilon _P\) is the rate of potential energy dissipation. Moreover, it is shown that the recent scaling laws for mixing efficiency in stably stratified turbulence in the absence of rotation, as exemplified in Garanaik & Venayagamoorthy (J. Fluid Mech. 867, 2019, pp. 323-333), are applicable as well for homogeneous and decaying RST. Results also highlight the ambiguity of the ratio N/f as a control parameter for the classification of small-scale RST, and thus for evaluating diapycnal mixing.

在没有施加剪切或强迫的情况下，使用均匀旋转分层湍流 (RST) 的30 个直接数值模拟（以\(1024^3\)分辨率）分析透湿（不可逆）混合。介绍了不同旋转和分层速率对能量学（特别是动能和势能的耗散率）的影响。数据也在一个新的参数框架内进行分析，使用湍流 Froude 和 Rossby 数\(Fr_t = \epsilon /Nk\)，\(Ro_t = \epsilon / fk\)，其中k是湍流动能，\(\ epsilon\)其耗散率，N浮力频率和f科里奥利参数。该框架用于说明地球物理流动中分层和旋转的相对幅度，并为解释\(Fr_t\)和\(Ro_t\)之间的关系作为地球物理环境中的相关动态参数提供了有用的工具。结果表明，与没有旋转的结果相比，非强制旋转不会影响不可逆混合系数 ( \(\Gamma =\epsilon _P/\epsilon\) ) 的大小，其中\(\epsilon _P\)是潜在的比率能量耗散。此外，它表明最近在没有旋转的情况下稳定分层湍流中混合效率的比例定律，如 Garanaik 和 Venayagamoorthy 所例示（J.流体机械。867, 2019, pp. 323-333)，也适用于同质和衰减的 RST。结果还强调了N / f比值作为小规模 RST 分类的控制参数的模糊性，从而用于评估透析混合。