Reduced-Order Modeling of Transonic Buffet Aerodynamics
Reduced-Order Modeling of Transonic Buffet Aerodynamics
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DOI：
10.1007/978-3-030-25253-3_49
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发表时间：
2018-11
期刊：
影响因子：
--
通讯作者：
M. Winter;C. Breitsamter
中科院分区：
文献类型：
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作者：
M. Winter;C. Breitsamter
在目前的工作中，基于非线性系统辨识的降阶建模框架被扩展并应用于跨音速抖振空气动力学的预测。为此，采用了与循环神经模糊模型和多层感知器神经网络相结合的外部动态过滤方法。为了校准模型，通过强制运动非定常雷诺平均纳维-斯托克斯模拟提供训练数据。开发模型的目的是有效计算时变积分量，例如气动力和力矩系数趋势，而不是详细的流动效应的分辨率。从基于识别的角度来看，挑战在于即使没有外部强迫或激励活跃，也会存在抖振流的自持不稳定性的再现。最后，展示了降阶模型的性能，用于预测包含主要抖振现象的情况下的空气载荷。在这方面，通过考虑 NACA 0012 机翼在跨音速自由流条件下经历超出抖振临界迎角的强制俯仰运动来测试该方法。与全阶参考解的比较表明，该模型捕捉到了非线性空气动力系统的本质特征。
In the present work, a reduced-order modeling framework based on nonlinear system identification is extended and applied concerning the prediction of transonic buffet aerodynamics. For this purpose, the external dynamic filtering approach combined with both a recurrent neuro-fuzzy model and a multilayer perceptron neural network is employed. In order to calibrate the model, training data are provided by means of a forced-motion unsteady Reynolds-averaged Navier-Stokes simulation. The intention of the developed model is the efficient computation of time-varying integral quantities such as aerodynamic force and moment coefficient trends in contrast to the resolution of detailed flow effects. From an identification-based point of view, the challenge lies in the reproduction of the self-sustained unsteadiness of the buffeting flow that is present even if no external forcing or excitation is active. Finally, the performance of the reduced-order model is demonstrated for predicting the air loads with respect to a case including predominant buffet phenomena. In this regard, the methodology is tested by considering the NACA 0012 airfoil at transonic freestream conditions undergoing a forced pitching motion beyond the buffet-critical angle of attack. A comparison with the full-order reference solution shows that the essential characteristics of the nonlinear aerodynamic system are captured by the proposed model.