标题： 跨音速条件下流通控制射流双稳态的动力模分解分析 显示英文标题

标题： Analysis of Circulation Control Jet Bi-Stability at Transonic Speeds via Dynamic Mode Decomposition

摘要： 利用数值模拟评估了在跨声速条件下使用环流控制的椭圆机翼上出现周期性射流脱离的现象。 当射流动量超过某一规定值时，射流开始从后缘表面周期性脱离。 该效应通过URANS计算以及数据驱动的方法（如动态模式分解DMD）进行了分析。 研究结果表明，这种被称为射流抖振的现象与上游主导激波解耦，表明射流不能再增强机翼的环流，从而终止了环流控制。 此外，发现双稳态的控制机制源于后缘激波和由射流产生的下游分离泡之间传播的压力反馈，以及由于脱离循环而引起的重新分配压力的二次反馈。 结论认为，双稳态不仅可以通过URANS有效捕捉，还可以通过约2%的总模态构建一个降阶模型来近似，这些模态包含了25%的模态影响，并且能够以98%的准确度重建压力场。 显示英文摘要

摘要： The phenomenon of a periodic jet detachment occurring on an elliptic airfoil utilizing circulation control at transonic speeds was evaluated using numerical simulations. As the momentum of the jet increases beyond a prescribed magnitude, the jet begins to detach periodically from the surface of the trailing-edge. The effect was analyzed by both URANS calculations as well as by data-driven methods such as the Dynamic Mode Decomposition (DMD). The results of the investigation showed that the effect, termed jet-buffet, is decoupled from the dominant shockwave located upstream, indicating that the jet can no longer augment the wing's circulation, and thus the termination of circulation control. Furthermore, it was found that the governing mechanism of the bi-stability originated from a feedback of pressure propagating between the trailing-edge shockwave and the downstream separation bubble produced by the jet, as well as a secondary feedback governing the pressure redistribution due to the detachment cycle. It was concluded that the bi-stability can not only be captured by URANS effectively but also approximated using a Reduced Order Model via 2% of the total modes, which encapsulate 25% of the modal influence as well as reconstructing the pressure field with 98% accuracy.