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中文核心期刊

激波边界层干扰流动中SST模型的贝叶斯修正

BAYESIAN CORRECTION OF SST MODEL FOR SHOCK WAVE-BOUNDARY LAYER INTERACTION FLOWS

  • 摘要: 广泛应用的湍流模型因其自身封闭参数存在可变性,使得对力/热等物理量的预测也存在不确定性。对湍流模型开展不确定度量化分析与改进,能够有效提升其预测精度和可信度。针对工程中常见的柱裙激波/边界层干扰流动问题,选择了剪切应力输运(shear stress transport, SST)湍流模型及加入二次本构关系(Quadratic Constitutive Relation,QCR)修正的剪切应力输运模型作为研究对象,对其封闭参数的不确定度进行量化研究,最终实现对湍流模型气动热预测能力的改进。具体步骤包括:首先通过采样得到先验样本以构建代理模型,其次对模型参数进行敏感性分析以甄别关键参数,最后通过贝叶斯推断方法实现对模型参数的校正,并在相似工况下验证了修正模型的适用性。结果表明,湍流模型在修正后,对于热流与压力的预测能力明显提高,同时两个模型具有的关键参数相同。此外,对湍流模型进行贝叶斯推断会使得计算得到的物理量发生明显变化,从而影响对分离区的预测,使得热流与压力预测更接近实验值。因此,使用贝叶斯推断方法并结合实验数据对湍流模型封闭参数进行校准,能够有效提高湍流模型对气动热的预测能力。

     

    Abstract: Widely used turbulence models have uncertainties in the prediction of physical quantities such as force/heat due to the variability of their own closure parameters. The uncertainty quantitative analysis and improvement of turbulence models can effectively improve their prediction accuracy and credibility. For the common problem of column skirt surge/boundary layer interference flow in engineering, the shear stress transport (SST) turbulence model and the shear stress transport model modified by adding Quadratic Constitutive Relation (QCR) are selected as the research objects to quantify the uncertainty of the closure parameter, and the uncertainty of the closing parameter is investigated. The uncertainty of the turbulence model and the shear stress transport model with the addition of the Quadratic Constitutive Relation (QCR) correction are investigated to quantify the uncertainty of their closure parameters, and ultimately to realize the improvement of the turbulence model's aerothermal prediction. The specific steps include: firstly, the a priori samples are obtained through sampling to construct the proxy model, secondly, the sensitivity analysis of the model parameters is carried out to screen the key parameters, and finally, the correction of the model parameters is realized through the Bayesian inference method, and the applicability of the modified model is verified under similar working conditions. The results show that the turbulence model, after correction, has significantly improved the prediction ability for heat flux and pressure, while the two models have the same key parameters. In addition, Bayesian inference of the turbulence model results in significant changes in the calculated physical quantities, which affects the prediction of the separation zone and makes the heat flux and pressure predictions closer to the experimental values. Therefore, calibrating the turbulence model closure parameters using Bayesian inference and incorporating experimental data can effectively improve the turbulence model's ability to predict aerodynamic heat.

     

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