可压缩瑞利–泰勒失稳的直接数值模拟及混合机理研究

Compressible Rayleigh-Taylor instability (RTI) and the induced turbulent mixing flows are of fundamental and applied interest to a wide range of phenomena in nature and the fields of engineering, such as supernovae and inertial confinement fusion, as well as the cutting-edge and bottle-neck research problems. The present joint project of NSFF intends to develop a high-accuracy and robust computing program for direct numerical simulations of compressible RTI and turbulent mixing. The primary interests are the effects of initial conditions and input parameters on the RTI evolution and turbulent mixing in strong compressible and high-density ratio environment. The focus is on exploration of the physical mechanism of compressible RTI turbulent mixing and evaluation of the validity of celebrated turbulence models, which may lay the theoretical and parametric groundwork for turbulence modeling of engineering interest. Another purpose of the present joint project is to strengthen the communication and cooperation between Peking University and Institute of Applied Physics and Computational Mathematics, to get an in-depth insight into the physical mechanism of compressible RTI turbulent mixing, and to improve the capability of accurate modeling.

可压缩瑞利-泰勒不稳定性(RTI)及湍流混合现象在自然界和工程界受到广泛关注，如超新星爆炸和惯性约束核聚变，也是科学研究的前沿和瓶颈问题。本联合基金项目拟开发三维高精度、强鲁棒的可压缩RTI及湍流混合的直接数值模拟程序，研究强压缩高密度比条件下RTI演化和湍流混合的初场和参数效应。本项目重点研究RTI湍流混合的内在机理，评估常见湍流模型的有效性，为建立适用于可压缩RTI湍流混合的工程湍流模型奠定理论和参数基础。通过本联合基金研究可以加强北京大学和北京应用物理与计算数学研究所的科研合作，加深对可压缩RTI混合问题物理机理的认识，提升精确建模能力。

本项目针对可压缩瑞利-泰勒不稳定性(RTI)及湍流混问题开展了直接数值模拟、湍流模式及混合机理研究。项目研究内容和取得的关键研究成果如下。. （1）开发了三维高精度、强鲁棒的可压缩流体界面不稳定性（RTI和RMI）及湍流混合的直接数值模拟程序，通过典型算例的直接数值模拟和实验数据对比，验证了计算程序的有效性和可靠性。. （2）对典型高密度比条件下不同初始参数的RTI和RMI 演化及湍流混合进行了直接数值模拟和理论研究，初步建立了直接数值模拟数据库，获得了扰动演化和湍流混合的初始条件和参数效应，并揭示了混合的物理机制。. （3）研究了RTI扰动演化的预测模型和湍流混合模拟模型，通过参数化量纲分析和数据分析给出了确定最优模型参数的方法论。. 总之，本项目研究圆满完成了项目计划书中的研究内容，达到了项目研究目标。部分成果已经发表在流体力学相关领域的核心期刊。