RANS predictions for high-speed flows using enveloping models
RANS predictions for high-speed flows using enveloping models
复制标题
使用包络模型对高速流进行 RANS 预测
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
G. Iaccarino
中科院分区：
文献类型：
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作者：
A. Mishra;G. Iaccarino
在这项研究中，我们概述了一种包络模型方法，用于估计RANS闭包的结构不确定性界限。该方法在雷诺应力张量的谱表示中结合了特征值和特征向量扰动。这种包络模型方法的基本原理详细说明和数学上的细微差别概述。该方法通过应用于分离湍流的典型情况得到了验证，同时与数值数据进行了对比。结果表明，该方法能够对感兴趣的数量的不确定性提供谨慎的估计。此外，仅使用两个特定的RANS模拟就可以产生工程效用的不确定性边界，从而最大限度地减少与不确定性估计相关的计算开销。然后，将该方法应用于超音速轴对称“淹没”射流。认知不确定性包络与基于RANS闭包预测的任意不确定性界限形成对比。该方法能够提供令人满意的高速流计算结果。
In this investigation, we outline an enveloping models methodology for estimating structural uncertainty bounds on RANS closures. This methodology incorporates both eigenvalue and eigenvector perturbations in the spectral representation of the Reynolds stress tensor. The underlying rationale of this enveloping models methodology are explicated in detail and the mathematical nuances are outlined. This methodology is validated via its application to a canonical case of separated turbulent flow, while contrasted against numerical data. It is exhibited that this procedure is able to provide prudent estimates on the uncertainty of quantities of interest. Furthermore, uncertainty bounds of engineering utility can be engendered using just two specific RANS simulations, minimizing the computational overheads associated with uncertainty estimation. Thence, this methodology is applied to a supersonic axisymmetric "submerged" jet flow. The epistemic uncertainty envelopes are contrasted against the aleatoric uncertainty bounds predicated upon the predictions of the RANS closure. The methodology is able to provide satisfactory results for this high-speed flow.