中文摘要：

考虑自由转捩的定常/非定常流动Navier-Stokes方程数值求解,对于翼型流动细节的精确模拟和气动力的精确预测均具有十分重要的意义。采用动模态分解（DMD）方法进行流动稳定性分析,再结合e N方法,提出了一套适用于翼型绕流的转捩预测新方法,称为DMD/e N方法。相比于传统的线性稳定性分析方法,DMD方法不需要求解附面层方程和线性稳定性方程,也没有引入平行流假设,具有更好的理论适用性和算法鲁棒性。开展了NLF0416、S809和SD7003等翼型的转捩预测数值验证研究,通过与实验结果以及与传统的基于线性稳定性分析的e N方法的比较,验证了本文所发展的转捩预测新方法在预测翼型的定常流动和非定常流动转捩方面的正确性,也表明了该方法具有解决含层流分离泡的翼型绕流转捩预测的能力。

英文摘要：

Transition prediction is crucial for the simulation of steady and unsteady flows,since it can improve the accuracy of predicting the aerodynamic forces as well as capturing the flow phenomena.By combining dynamic mode decomposition（DMD）and eN method,a novel transition prediction method for flows over airfoils is proposed.Compared with conventional linear stability-analysis-based eN method,DMD requires neither the solution of boundary layer and linear stability equations,nor the assumption of parallel flows,and has better applicability in theory and is more algorithmically robust.Transition prediction of steady flows around NLF0416 and S809airfoils and unsteady flow around SD7003 airfoil are carried out.The predicted transition locations are in reasonably good agreement with the experimental data and the results of eN method based on linear stability analysis.It is shown that the proposed DMD/eN method is feasible for transition prediction for steady and unsteady flows over airfoils,including the flows with laminar separation bubbles.