发表机构
University of Nevada, Reno（内华达大学里诺分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过直接数值模拟和能量分配方法，揭示前缘涡系能量传递主导低雷诺数俯仰有限翼的颤振起始，并指出前缘为颤振抑制的关键目标。
AI 中文摘要
颤振起始由结构上的气动功符号决定，但周期积分功并不能揭示这种能量传递的来源。我们对展弦比为2的NACA 0015机翼在$Re=1000$下俯仰运动的不可压缩流动进行了直接数值模拟，并使用瓣分辨力-力矩分配方法识别气动弹性功率的涡旋贡献。净能量传递在$U^*=4.25$附近改变符号。在这一转变过程中，上前缘贡献从$U^*=2$时的阻尼变为接近起始时的激励，并在$U^*=6$时成为最大的正贡献。在稳定性边界附近，正的前缘功几乎被负的后缘功所平衡。这种变化伴随着前缘压力足迹的重组以及气动力矩与俯仰速率之间相位差的减小，将颤振起始与前缘涡系统的时间联系起来。一次缓慢增长的振幅模拟恢复了有限振幅能量边界，而自由俯仰计算证实了预测的不稳定性。随着运动接近其极限环，能量路径重新分布，响应频率匹配的强迫计算重现了大振幅能量预算。这些结果区分了触发颤振的机制与饱和响应的机制，并确定前缘为颤振抑制的自然目标。
英文摘要
Flutter onset is determined by the sign of the aerodynamic work on the structure, but cycle-integrated work does not reveal where this energy transfer originates. We perform direct numerical simulations of incompressible flow over an aspect-ratio-two NACA 0015 wing pitching at $Re=1000$ and use lobe-resolved force-moment partitioning to identify the vortical contributions to aeroelastic power. The net energy transfer changes sign near $U^*=4.25$. Across this transition, the upper leading-edge contribution changes from damping at $U^*=2$ to excitation near onset and becomes the largest positive contribution at $U^*=6$. Near the stability boundary, positive leading-edge work is nearly balanced by negative trailing-edge work. This change is accompanied by a reorganization of the leading-edge pressure footprint and a reduction in the phase difference between aerodynamic moment and pitch rate, linking flutter onset to the timing of the leading-edge vortex system. A single slowly growing-amplitude simulation recovers the finite-amplitude energy boundary, while a free-pitching calculation confirms the predicted instability. As the motion approaches its limit cycle, the energy pathways redistribute, and a response-frequency-matched forced calculation reproduces the large-amplitude energy budget. These results distinguish the mechanism that triggers flutter from that which saturates the response and identify the leading edge as a natural target for flutter suppression.
Comments15 pages, 5 figures
