AI 中文总结
该研究提出一种物理约束浮力-阻力模型，结合局部界面动力学与全局质量守恒，可跨密度比统一预测RT和RM混合宽度，无需逐案调整即可准确描述不同混合场景的演化。
AI 中文摘要
准确预测瑞利-泰勒（RT）和里希特迈耶-梅什科夫（RM）湍流混合层的宏观宽度，是惯性约束聚变和超新星动力学的核心需求。然而，气泡-尖峰不对称性、密度比依赖性及非稳态驱动构成了持续的闭合挑战：现有的低阶浮力-阻力模型难以用单一模型和系数集准确描述不同混合问题。我们将局部界面动力学与全局质量守恒相结合，分别构建了适用于气泡和尖峰界面的浮力-阻力方程。该模型未采用共享或固定的经验系数，而是在两侧保留独立的惯性、浮力和阻力系数，并允许它们随密度比独立变化。基于气泡侧状态标度、RT/RM相似关系、平均组成剖面及端点渐近性，可在无需逐案拟合的情况下共同约束全部六个有效系数。剖面形状参数$c$用于标记不同的内部组成状态，且可从线性电动马达实验测得的RT尖峰标度中预先选定。随后，该模型无需针对RM尖峰数据重新校准，即可交叉预测RM尖峰指数，且根据其构造可恢复低阿特伍德数下的气泡-尖峰对称性，以及高密度比下的自由下落RT尖峰和弹道RM尖峰极限。通过与恒加速度和变加速度RT混合、脉冲后RM演化及Nova激光减速的测试对比，结果表明，该闭合关系可描述跨密度比和加速度历史的混合宽度演化，无需针对特定案例进行重新调整，同时减少了高密度比下尖峰的过度增长。这种具有物理解释性、渐近一致性的框架，可实现宽密度比RT混合和脉冲后RM混合的跨问题预测。
英文摘要
Accurate prediction of the macroscopic width of Rayleigh--Taylor (RT) and Richtmyer--Meshkov (RM) turbulent mixing layers is central to inertial confinement fusion and supernova dynamics. However, bubble--spike asymmetry, density-ratio dependence and unsteady forcing pose a persistent closure challenge: existing low-order buoyancy--drag models struggle to describe different mixing problems accurately with one model and coefficient set. We combine local front dynamics with global mass conservation in separate buoyancy--drag equations for the bubble and spike fronts. Rather than imposing shared or fixed empirical coefficients, the model retains separate inertia, buoyancy and drag coefficients on the two sides and allows them to vary independently with density ratio. Given the bubble-side state scalings, RT/RM similarity relations, a mean-composition profile and endpoint asymptotics jointly constrain all six effective coefficients without case-by-case fitting. A profile-shape parameter $c$ labels distinct internal composition states and is selected a priori from RT spike scaling measured in linear-electric-motor experiments. The model then cross-predicts the RM spike exponent without recalibration to RM spike data and, by construction, recovers low-Atwood-number bubble--spike symmetry and the high-density-ratio free-fall RT-spike and ballistic RM-spike limits. Tests against constant- and variable-acceleration RT mixing, post-impulse RM evolution and Nova laser deceleration show that one closure describes mixing-width evolution across density ratios and acceleration histories without case-specific retuning, while reducing excessive spike growth at high density ratio. This physically interpretable, asymptotically consistent framework enables cross-problem prediction of wide-density-ratio RT and post-impulse RM mixing.
