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arXiv 2203.02093physics.flu-dyn
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变密度湍流混合模型的多保真度验证

Multi-fidelity validation of variable-density turbulent mixing models

Benjamin Musci, Britton Olson, Samuel Petter, Gokul Pathikonda, Devesh Ranjan

摘要:

在这项研究中,合奏的实验数据,并利用比较和验证两个模型中使用的模拟变密度,可压缩湍流混合。虽然这种模型(雷诺平均Navier Stokes和大涡模拟)已被广泛验证与更多的规范流在以前的研究中,本方法提供了新颖的几何形状的复杂性,合奏为基础的验证,和均匀的计算框架上的模型进行测试。此外,所有的实验和计算任务都是由作者完成的,这导致了与其数字孪生模型紧密耦合的实验配置。描述了实验发散激波管装置及其数据获取方法,并在模拟空间中进行了复制。忽略界面处湍流混合的二维欧拉模型使用高斯过程优化到实验数据。然后,该模型作为基础的2D RANS和3D LES的研究,从实验中的混合层数据进行比较。RANS只在后期流动发展时间与实验数据吻合良好。LES合奏一般表现出良好的协议与实验数据,但显示的初始条件的表征敏感性。分辨率依赖的行为也观察到某些高阶统计的兴趣。总的来说,LES模型成功地捕捉到发散的几何形状,可压缩性,并结合非线性不稳定性的问题固有的影响。混合宽度及其增长率的成功预测突出了三个不同的制度的发展中存在的不稳定性,每个与以前研究的不稳定性的相似之处。

英文摘要:

In this study, ensembles of experimental data are presented and utilized to compare and validate two models used in the simulation of variable density, compressible turbulent mixing. Though models of this kind (Reynolds Averaged Navier Stokes and Large Eddy Simulations) have been validated extensively with more canonical flows in previous studies, the present approach offers novelty in the complexity of the geometry, the ensemble based validation, and the uniformity of the computational framework on which the models are tested. Moreover, all experimental and computational tasks were completed by the authors which has led to a tightly coupled experimental configuration with its digital twin. The experimental divergent shock tube facility and its data acquisition methods are described and replicated in simulation space. A 2D Euler model which neglects the turbulent mixing at the interface is optimized to experimental data using a Gaussian process. This model then serves as the basis for both the 2D RANS and 3D LES studies that make comparisons to the mixing layer data from the experiment. RANS is shown to produce good agreement with experimental data only at late flow development times. The LES ensembles generally show good agreement with experimental data, but display sensitivity to the characterization of initial conditions. Resolution dependent behavior is also observed for certain higher-order statistics of interest. Overall, the LES model successfully captures the effects of divergent geometry, compressibility, and combined non-linear instabilities inherent to the problem. The successful prediction of mixing width and its growth rate highlight the existence of three distinct regimes in the development of the instability, each with similarities to previously studied instabilities.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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