关键词: 变体机翼, 动力学模态降阶, 频率加权, 拍动, 重构

Abstract: Morphing airfoil is one of the essential solutions to improve the maneuverability performance of the aircraft, high lift and low drag, and to meet the variable flighting conditions. Exploring the mechanism of the wing deformation influ-ence on the flow is the precondition of control. A frequency-weighted ordering approach of the dynamic mode de-composition is proposed to analyze the influence mechanism of trailing edge flapping of a morphing airfoil. The fre-quency-weighted method is compared with conventional ways, like initial value and norm, concerning the numerical simulation results and experimental data under different working conditions. The 2nd modal frequencies obtained by the frequency-weighted method match the flapping frequencies, indicating its ability to reveal the influence of the periodical flapping on the flow inner structure and wake. Based on the numerical simulation data, with the same number of reconstructed modes and flapping frequency of 300 Hz, the errors of frequency-weighted, initial value, and norm methods are 0.39%, 0.58%, and 3.25%, respectively. Based on the PIV test data, the errors become 7.56%, 8.77%, and 10.56%. The frequency-weighted method has the slightest mistake and can be better used for the active flapping morphing wing's flow analysis and subsequent feedback control.

Key words: morphing airfoil, dynamic mode decomposition, frequency-weighted, flapping, reconstruction