ABSTRACT Obtaining accurate solutions of unsteady flows during the design process of an aircraft can be a highly demanding task. Reduced basis methods (RBM) are commonly used to reduce the number of degrees of freedom while preserving high accuracy. RBM based on Proper Othogonal Decomposition (POD) have been extensively used but limitations exist with unsteady problems, where the temporal nonlinear dynamics of the flow needs to be addressed carefully. The accuracy in reconstructing nonlinear unsteady flows by means of RBM for a specific class of impulsively started lifting bodies is addressed. The snapshot POD approach and the recent Spectral POD will be comparatively studied to assess their capacity to reconstruct unsteady flows. The periodic motion past a cylinder will be considered as a benchmark test while the impulsive start of a 2D three-element airfoil and a 3D wing in high-lift configurations will be considered as use cases.

中文翻译：

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POD模式能量重新分配对脉冲启动翼型和机翼非定常流动的流动重建的影响

摘要 在飞机的设计过程中获得非定常流动的准确解是一项要求很高的任务。缩减基方法 (RBM) 通常用于减少自由度的数量，同时保持高精度。基于适当正交分解 (POD) 的 RBM 已被广泛使用，但非定常问题存在局限性，需要仔细解决流动的时间非线性动力学问题。解决了通过 RBM 为特定类别的脉冲启动提升体重建非线性非定常流的准确性。将比较研究快照 POD 方法和最近的光谱 POD 以评估它们重建不稳定流的能力。