| 双三角翼非定常俯仰运动实验与数值模拟 |
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| 作者姓名： | 赵悦 胡天翔 陈庆民 刘沛清 |
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| 作者单位： | 北京航空航天大学陆士嘉实验室, 北京100191;北京航空航天大学陆士嘉实验室, 北京100191;北京航空航天大学陆士嘉实验室, 北京100191;北京航空航天大学陆士嘉实验室, 北京100191 |
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| 基金项目： | 国家自然科学基金118504104440国家自然科学基金11772033国家自然科学基金117221202 |
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| 摘 要： | 文章针对双三角翼大振幅正弦俯仰运动过程中的非定常载荷和流动特性开展了实验与数值模拟研究，并与相同主翼后掠角的单三角翼进行了对比.实验研究在低速回流式水槽中开展，所采用的实验模型为边条后掠角为75°，主翼后掠角为50°的双三角翼全模，俯仰运动的旋转轴位于主翼弦长的2/3处，振幅为0~60°，运动的缩减频率k=0.03，0.06，0.12，0.24，0.48.实验Reynolds数以主翼弦长为参考Re=1.69×104.在水槽的测力实验中，发现非定常流动力的迟滞现象，并且随着非定常运动缩减频率的增大，流动的迟滞效应也随之增大.与相同主翼后掠角的单三角翼相比，双三角翼的迟滞环在低缩减频率下更小，但随着缩减频率的增大，这种差距逐渐减小.在数值模拟研究中，采用DDES湍流模型对俯仰双三角翼的流场进行了数值模拟.流场结果表明，在较低的缩减频率下，主翼吸力面的前缘涡是影响气动力的主要因素，非定常流动力的迟滞效应主要与前缘涡在上仰过程中的延迟破裂和下俯过程中的延迟恢复有关；在较高的缩减频率下，机翼前缘涡对气动力的影响减小，由机翼俯仰角速度而产生的环量力成为了气动力的主导因素，因此在较高缩减频率下，单三角翼与双三角翼的升力特性趋于一致.
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| 关 键 词： | 双三角翼 迟滞环 俯仰运动 前缘涡 环量力 |
| 收稿时间： | 2019-07-22 |
Experimental and Numerical Studies on Large-Amplitude-Pitching Double-Delta Wings |
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| Affiliation: | Lu Shijia Laboratory, Beihang University, Beijing 100191, China |
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| Abstract: | In current study, the unsteady loads and flow characteristics of a 75°/50° double-delta wing in large amplitude sinusoidal pitching motion were studied experimentally and numerically, and compared with a 50° sweep nonslender delta wing. The experimental study was conducted in a water channel facility. A wide variety of flow conditions were considered in the present study by systematically varying the reduced frequency (k=0.03~0.48), while keeping the pitching amplitude and the Reynolds number fixed. The hysteresis phenomenon of unsteady force was found in the water channel force measurements. The hysteresis effect increases with the increase of reduced frequency. Compared the 50° delta wing, the hysteresis loop of double-delta wing is smaller at low reduced frequency. As the reduced frequency increases, such difference becomes smaller. In the numerical simulation, the DDES turbulence model was used to simulate the flow field of the pitching double-delta wing. The results of flow field show that the leading-edge vortex on suction surface is the main factor affecting aerodynamic force at low reduced frequencies, and the hysteresis effect of unsteady flow force is mainly related to delayed breakdown of the leading-edge vortices in pitching up and the delayed restoration of the leading-edge vortices in pitching down. At high reduced frequencies, the influence of leading-edge vortices on aerodynamic forces decreases, and the additional circulatory force generated by pitch angular velocity becomes the dominant factor of aerodynamic forces. Therefore, the lift characteristics of delta wing and double-delta wing tend to be the same at high reduced frequencies. |
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