破碎波激发湍流的数值模拟研究进展

Advances in numerical simulation of turbulence excited by breaking waves

  • 摘要: 波浪破碎过程伴随着大量空气卷入,会形成水、气充分混合的混相湍流,对其发展数值模拟方法与湍流封闭模型是当前研究的难点。本文综述了混相湍流的数值模拟研究进展,重点介绍了高密度比两相流模拟的数值稳定性问题和解决方案。针对传统方法在界面捕捉与动量方程求解格式不一致导致的数值不稳定性,近期提出的密度预估-同步法通过显式求解质量输运方程,实现了高密度比条件下的稳定计算。本文还详细阐述了该方法的控制方程、时空离散格式及界面捕捉技术,并通过经典算例验证了其有效性。此外,以射流、尾流和船首波破碎为例,分析了混相湍流的流动特征,揭示了弗劳德数对湍动能和湍流质量通量的主导影响。在封闭模型方面,对比了代数型与动力学模型的优劣,指出动力学模型虽更具理论潜力,但需进一步解决组合项封闭问题。本文为混相湍流的模拟与建模提供了系统参考,并展望了未来研究方向,如建立标准的算例数据库和通过GPU并行优化提高计算效率等。

     

    Abstract: Wave breaking is accompanied by the entrainment of air, forming mixed-phase turbulent flow with fully mixed air and water. The numerical simulation methods and closure model for mixed-phase turbulence are challenging topics in current research. This paper reviews the recent progress in numerical investigations of mixed-phase turbulence, with a focus on the numerical stability issues and solutions for high-density-ratio two-phase flow simulations. To address the numerical instability caused by the inconsistency between front-capturing and momentum equation discretization in traditional methods, the recently proposed density-prediction-synchronization method achieves stable computation under high-density-ratio conditions by explicitly solving the mass transport equation. Furthermore, the governing equations, spatiotemporal discretization schemes, and front-capturing techniques of this method are elaborated in detail, and its effectiveness is validated through classic test cases. Additionally, taking jet flow, wake flow, and bow wave breaking as examples, the flow characteristics of mixed-phase turbulence are analyzed, revealing the dominant influence of the Froude number on turbulent kinetic energy and turbulent mass flux. Regarding closure models, the advantages and limitations of algebraic and dynamic models are compared, highlighting that while dynamic models show greater theoretical potential, further research is needed to address the closure of combined terms. This study provides a systematic reference for the simulation and modeling of multiphase turbulence and outlines future research directions, such as establishing a standardized benchmark database and improving computational efficiency through GPU parallel optimization.

     

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