...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Aerospace science and technology >Aerodynamic characteristics of flexible wings with leading-edge veins in pitch motions
【24h】

Aerodynamic characteristics of flexible wings with leading-edge veins in pitch motions

机译：俯仰运动中具有前缘静脉的柔性机翼的空气动力学特性

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

To demonstrate the effects of wing deformations on aerodynamic performances during the wing reversal, aerodynamic force/torque and flow vector-fields were measured. Wing models consisted of wing planes with various thicknesses and two leading-edge veins, which obstructed spanwise deformations (Case 1 as a rigid wing and Cases 2 to 4 as flexible wings). They also underwent three different pitching periods (t/T-R,T-alpha = 0.1, 0.2, and 0.4) to determine the distinct changes in vortical structures and corresponding aerodynamic characteristics. Flexible wings generally showed a negative camber in the stroke motion, causing poor aerodynamic performance relative to a rigid wing. This was also related to the positive camber and camber change to the negative during the pitch motions. After the start of the stroke, the positive camber caused separated and weakened tip vortex (TV) structures, hindering leading-edge vortex (LEV) formations around the wingtip. Depending on the LEV shedding, the flexible wings generated less aerodynamic forces than the rigid wing in stroke motion. During the pitch motions, on the other hand, the dynamic cambers influenced rotational mechanisms such as the wing-wake interaction and rotational force, causing higher or less initial lift increment. As the t/TR,a increased, the amount of the lift augmentation decreased due to the weakened wing-wake interaction, instead showing a downwash. At t/T-R,T-alpha = 0.4, however, the higher initial lift peak was occurred due to the absence of distinct trailing-edge vortex (TEV) generation during the wing-reversal. This lack of the U_TEV2 led to the decline of the downwash. Thus, the delayed U_LEV1 dispersal and the U_TEV2 traces generated similar induced flows to the wing-wake interaction, resulting in higher lift augmentation. Furthermore, Case 2 achieved higher lift augmentations than the other cases in all pitching periods. The slight wing deformations not only reduced the distance between the vortices and the wing surface, but also caused the delayed vortex dispersals. These induced the stronger rapid flows toward the wing surface, causing the higher initial lift peaks. Case 2 also had the highest C-L/C-p,C-t at t/T-R,T-alpha = 0.1 than the other cases. These results suggest that the flexible wing with leading-edge veins can have higher aerodynamic efficiency in its specific chordwise flexibility range. (C) 2019 Elsevier Masson SAS. All rights reserved.
机译：为了证明机翼变形在机翼反转过程中对气动性能的影响，测量了气动力/扭矩和流矢量场。机翼模型由厚度各异的机翼平面和两条前缘静脉组成，这些翼型阻碍了翼展方向的变形（案例1为刚性机翼，案例2至4为柔性机翼）。他们还经历了三个不同的俯仰周期（t / T-R，T-alpha = 0.1、0.2和0.4），以确定旋涡结构和相应的空气动力学特性的明显变化。柔性机翼在冲程运动中通常显示为负弯度，相对于刚性机翼，其导致较差的空气动力性能。这也与俯仰运动中的正外倾角和外倾角变化有关。冲程开始后，正外倾角导致尖端涡旋（TV）结构分离并减弱，从而阻碍了翼尖周围的前沿涡旋（LEV）形成。根据LEV的脱落情况，在机翼运动中，柔性机翼产生的气动力要小于刚性机翼。另一方面，在俯仰运动期间，动态外倾角影响旋转机构，例如机翼-尾翼相互作用和旋转力，从而导致较高或较小的初始升力增量。随着t / TR，a的增加，升力的增加量由于机翼-尾翼相互作用的减弱而减少，而呈现出下冲。然而，在t / T-R，T-alpha = 0.4时，由于在机翼反转过程中没有明显的后缘涡流（TEV）产生，因此出现了较高的初始升力峰。 U_TEV2的缺乏导致冲洗下降。因此，延迟的U_LEV1扩散和U_TEV2轨迹产生了与机翼-尾流相互作用相似的诱导流，从而导致更高的升力。此外，案例2在所有投球期间均实现了比其他案例更高的提升力。轻微的机翼变形不仅缩短了涡流与机翼表面之间的距离，而且导致了涡流扩散的延迟。这些引起朝向机翼表面的较强的快速流动，从而引起较高的初始升力峰值。案例2在t / T-R，T-alpha = 0.1时也比其他案例具有最高的C-L / C-p，C-t。这些结果表明，具有前缘静脉的柔性翼在其特定的弦向柔性范围内可以具有更高的空气动力学效率。 （C）2019 Elsevier Masson SAS。版权所有。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号