Transonic buffet instability: From two-dimensional airfoils to three-dimensional swept wings
Transonic buffet instability: From two-dimensional airfoils to three-dimensional swept wings
复制标题
跨音速抖振不稳定性：从二维翼型到三维后掠翼
DOI：
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发表时间：
2019
影响因子：
2.7
通讯作者：
J. Robinet
中科院分区：
文献类型：
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作者：
E. Paladini;Samir Beneddine;J. Dandois;D. Sipp;J. Robinet
本研究的目的是通过全局稳定性分析来解释跨音速抖振现象从二维翼型到三维后掠翼的演变。对于二维抖振，在后掠30°机翼的情况下，激波振荡频率增加了4~7倍，分离边界层中的三维图形被对流到船外。Crouch et al.访问数/每百万人：Reach for[J.太棒了。224,924(2007)]通过线性化雅可比矩阵的实正复本征值的出现来解释二维跨音速抖动现象。在无限大无后掠翼的情况下，本文的研究表明，实际上存在两种不稳定模式：克劳奇等人已经发现的二维跨音速抖振模式。访问数/每百万人：Reach for[J.628,357(2009)]和强放大的三维零频模式。后者在分离的边界层中表现出规律性的模式，这与Iovnovich等人所命名的所谓的自助式细胞有关。[AIAA J.53,449(2015)]。非零后掠角在机翼上产生一个横跨方向的速度分量，该速度分量对流单元。
下船了。这影响了在未扫描情况下识别的两种模式：二维模式受到扫描的弱衰减，而三维抖动单元模式，即使弱衰减，也保持强烈的不稳定，并且现在呈现出随扫描角度增加的非零频率。在扫掠角度为30°时，最不稳定的三维模式的频率和波长与数值计算结果符合得很好
以及机翼三维跨音速抖振的实验值。对三维模式的造波分析表明，失稳的核心几乎完全位于分离区，最大值沿分离线。相反，二维抖动模式的造波器在整个过程中表现出更强的值
The objective of the present study is to explain the evolution of the transonic buffet phenomenon from two-dimensional airfoils to three-dimensional swept wings by a global stability analysis. With respect to two-dimensional buffet, shock oscillation frequency increases by a factor of 4 to 7 in the case of a swept 30° wing and three-dimensional patterns in the detached boundary layer are convected outboard. Crouch et al. [J. Comput. Phys. 224, 924 (2007)] explained the two-dimensional transonic buffet phenomenon by the appearance of a real positive complex eigenvalue of the linearized Jacobian matrix. In the case of an infinite unswept wing, the present study shows that two unstable modes actually exist: The two-dimensional transonic buffet mode already identified by Crouch et al. [J. Fluid Mech. 628, 357 (2009)] and a strongly amplified three-dimensional zero-frequency mode. The latter exhibits regular patterns in the separated boundary layer, which relates to the so-called buffet cells as named by Iovnovich et al. [AIAA J. 53, 449 (2015)]. The nonzero sweep angle generates a spanwise velocity component on the wing which convects the cells
outboard. This impacts both modes identified in the unswept case: The two-dimensional mode is weakly damped by the sweep while the three-dimensional buffet cells mode, even if weakly damped, remains strongly unstable and now exhibits a nonzero frequency which increases with the sweep angle. The frequency and wavelength of the most unstable three-dimensional mode for a sweep angle of 30° agree well with numerical
and experimental values of the three-dimensional transonic buffet on wings. The analysis of the wavemaker of the three-dimensional modes indicates that the core of the instability is nearly solely located in the separated region, with a maximum along the separation line. In contrast, the wavemaker of the two-dimensional buffet mode exhibits stronger values all along the