雷诺应力张量特征空间扰动的自洽性改进用于不确定性量化
Improved self-consistency of the Reynolds stress tensor eigenspace perturbation for uncertainty quantification
AI总结：
针对RANS湍流模型不确定性量化中雷诺应力张量特征空间扰动实现的自洽性问题，提出改进实现方法，确保扰动后的特征值与原始值保持线性相关。
摘要：
在雷诺平均纳维-斯托克斯（RANS）模拟中，湍流闭合模型的局限性在很大程度上有助于计算流体力学（CFD）不确定性的产生。在物理限制范围内扰动雷诺应力张量的谱表示，是多种商业和开源CFD求解器中为获取RANS湍流模型认知不确定性估计而普遍采用的做法。近期研究表明，由于求解器即将出现的稳定性问题，需要对所考虑的扰动雷诺应力张量的大小进行调节。本文指出，随之而来的常见实现可能导致所得到的扰动雷诺应力张量出现非预期的状态。特征向量扰动与调节因子的组合实际上可能产生调节后的特征值，这些特征值不再与原始未扰动和完全扰动的特征值线性相关。因此，计算实现不再符合特征空间扰动框架的概念思想。我们针对其自洽性验证了概念描述的实现。恰当地体现基本概念，需要制定一种计算实现，以改进雷诺应力张量扰动的自洽性。
英文摘要：
The limitations of turbulence closure models in the context of Reynolds-averaged NavierStokes (RANS) simulations play a significant part in contributing to the uncertainty of Computational Fluid Dynamics (CFD). Perturbing the spectral representation of the Reynolds stress tensor within physical limits is common practice in several commercial and open-source CFD solvers, in order to obtain estimates for the epistemic uncertainties of RANS turbulence models. Recent research revealed, that there is a need for moderating the amount of perturbed Reynolds stress tensor tensor to be considered due to upcoming stability issues of the solver. In this paper we point out that the consequent common implementation can lead to unintended states of the resulting perturbed Reynolds stress tensor. The combination of eigenvector perturbation and moderation factor may actually result in moderated eigenvalues, which are not linearly dependent on the originally unperturbed and fully perturbed eigenvalues anymore. Hence, the computational implementation is no longer in accordance with the conceptual idea of the Eigenspace Perturbation Framework. We verify the implementation of the conceptual description with respect to its self-consistency. Adequately representing the basic concept results in formulating a computational implementation to improve self-consistency of the Reynolds stress tensor perturbation
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。
