界面不稳定性诱导的湍流混合问题的RANS统一预测新思路  

A new idea for the unified RANS predictions of turbulent mixing induced by interfacial instabilities

作　　者：谢寒松 肖梦娟 张又升[1,2,3] XIE Hansong;XIAO Mengjuan;ZHANG Yousheng(HEDPS and Center for Applied Physics and Technology,Peking University,Beijing 100871,China;Institute of Applied Physics and Computational Mathematics,Beijing 100094,China;National Key Laboratory of Computational Physics,Beijing 100088,China)

机构地区：[1]北京大学高能量密度物理数值模拟教育部重点实验室,应用物理与技术研究中心,北京100871 [2]北京应用物理与计算数学研究所,北京100094 [3]计算物理全国重点实验室,北京100088

出　　处：《空气动力学学报》2024年第9期1-13,I0001,共14页Acta Aerodynamica Sinica

基　　金：国家自然科学基金(12222203,11972093,12002059)。

摘　　要：准确预测由Rayleigh-Taylor(RT)、Richtmyer-Meshkov(RM)和Kelvin-Helmholtz(KH)等流体力学界面不稳定性诱导的湍流混合问题具有重要的科学意义和工程价值。在工程实践中,利用雷诺平均湍流模型(Reynolds-averaged Navier-Stokes,RANS)模拟上述问题是当前及可见的未来最主流的方法。RANS模型主要包括物理模型和模型系数两方面。然而,在实际工程中,存在各类复杂性问题及其相互耦合,使得采用同一套RANS模型统一预测不同混合问题变得极具挑战,而这又是RANS模型能落地工程应用的前提条件。为解决上述问题,本研究直面工程应用,基于整体论思维观提出了实现RANS渐近理想统一预测的新思路,给出了系统确定湍流混合模型系数的新方法,并将其应用至混合领域内的k-L、k-ε和BHR三类(含亚类)主流的RANS混合模型,均实现了同一套湍流混合模型对不同混合问题的统一预测,证明了所提思路和方法在混合领域的适用性和鲁棒性。本工作可为RANS湍流混合模型的工程化应用奠定基础,其核心思路也可望延拓应用至其他领域的湍流模型上。Accurate predictions of turbulent mixing phenomena induced by interfacial instabilities such as Rayleigh-Taylor(RT),Richtmyer-Meshkov(RM),and Kelvin-Helmholtz(KH)hold significant scientific and engineering importance.In engineering practice,utilizing Reynolds-averaged Navier-Stokes(RANS)model,which is mainly consisted of physical model and model coefficients,to simulate the aforementioned problems is currently and foreseeably the mainstream approach.However,the coupling of multiple complexities in actual engineering problems poses a great challenge for RANS models to uniformly predict different mixing problems.To address that,based on engineering application viewpoint,this study firstly proposes an asymptotic-ideal unified RANS prediction idea and a new method for determining turbulence mixing model coefficients.Then these concepts are applied to the three mainstream RANS mixing models in mixing field.Finally,this study systematically verifies the ability of the model in predicting different mixing problems with the same set of model and coefficients.Here,the investigated problems include both the basic problems,i.e.classical RT,RM,and KH mixing,and complex problems,i.e.re-shocked RM mixing,RT mixing with initial tilted interface and spherical implosion mixing.The temporal evolutions of mixing width agree well with the existing experiments or high-fidelity numerical simulations.This study systematically verifies the applicability and robustness of the asymptotic-ideal unified RANS predictions idea and methodology for determining model coefficients in turbulent mixing field.This work lays a solid foundation for the engineering application of RANS turbulence mixing models,and its core idea is expected to be applied to turbulence models in other fields.

关 键 词：湍流混合 统一预测 RANS模型 模型系数 

分 类 号：O241[理学—计算数学]