基于合成双射流的边条翼大迎角前缘涡控制研究

Numerical study of leading-edge vortex control of a strake-wing at large angles of attack based on Dual Synthetic Jets

  • 摘要: 边条翼在大迎角状态下会发生前缘涡涡破裂现象,气动性能显著降低,为解决这一问题,本研究提出一种基于合成双射流的涡破裂控制方法。在76°/40°边条翼的边条涡扫掠路径外侧安装合成双射流激励器,有效影响了边条涡的流动发展,改善了飞行器气动特性。结果表明,在自由来流马赫数为0.1情况下,施加控制后能推迟各迎角下的边条涡破裂点,在40°迎角时,涡破裂延迟量达到8.4%根弦长;同时,升力系数也得到了显著提升,在35°迎角时升力增量最大,达到7.51%。合成双射流激励器的两股射流以反相方式作用,持续推动低能气流同向旋转,实现了能量的有效注入,增强了边条涡抵抗逆压梯度的能力,延长了高速流动的流向距离,从而扩大了背风面的低压区面积,增加了涡升力。合成双射流对边条翼的气动力和涡破裂现象的控制效果显著,显示出其在细长机翼姿态控制方面的巨大潜力。

     

    Abstract: Strake wings at large angles of attack experience significant degradation in aerodynamic performance due to the leading-edge vortex breakdown phenomenon, the effective control of which, however, has yet to be thoroughly explored. This study proposes an innovative control method utilizing dual synthetic jets to delay the leading-edge vortex breakdown. The results indicate that the aerodynamic performance of a 76°/40° strake wing can be improved by installing dual synthetic jet actuators away from the sweep path of the leading-edge vortex. The proposed control method can delay the strake vortex breakdown and thereby increase the lift coefficient at a wide range of the angle of attack (AoA). For instance, the vortex breakdown is delayed by 8.4% of the chord length at AoA=40°; the lift coefficient is increased by 7.51% at AoA=35°. The reason for such a significant improvement in aerodynamic performance is the effective energy injection, achieved by an anti-phase operating manner of two jets that continuously pushes low-energy fluids to rotate in the same direction. This operation method enhances the leading-edge vortex’s capability to withstand the adverse pressure gradient, lengthens the chordwise extent of high-speed flows, and expands the area of the low-pressure zone on the leeward side, thereby increasing the vortex lifting force. The above results demonstrate the dual synthetic jets’s potential in the attitude control of slender wings.

     

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