| 内聚锥形激波的非均匀强化与结构演变特征 |
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| 作者姓名： | 姬隽泽 张恩来 司东现 李祝飞 杨基明 |
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| 作者单位： | 中国科学技术大学, 安徽合肥 230027 |
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| 基金项目： | 国家自然科学基金11872356国家自然科学基金11772325国家自然科学基金11621202 |
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| 摘 要： | 以高超声速内转式进气道流动中的激波汇聚问题为背景，考虑工程实际中的来流和壁面几何条件这两个关键因素，分别提出了以来流攻角为研究参数的非轴向来流内锥流动模型，和以长/短轴比为研究参数的椭圆入口内锥流动模型.采用激波风洞实验观测和数值模拟相结合的方法，揭示了两类流动中激波的非均匀汇聚特征.结果表明:由来流攻角引起的激波初始沿周向强度分布的不均匀性会在汇聚过程中被放大，迎风面和背风面的激波差异不断加剧；来流攻角越大，初始激波强度不均匀性越强，在汇聚过程中激波面越容易出现不连续的拐折，且出现拐折后激波的汇聚效应会被削弱.由椭圆入口形成的等强度激波在初始时周向的几何不均匀性使激波在汇聚过程中出现沿长/短轴方向的强度差异，激波沿长轴方向上的强度增加更迅速；椭圆长/短轴比越大，激波初始几何不均匀性越强，在汇聚过程中长/短轴两个方向激波强度差异凸显得越快，波面越容易出现不连续的拐折，进而削弱激波的汇聚.在偏离轴对称达到一定程度时，这两种条件下的激波汇聚都会出现汇聚中心处从Mach反射向规则反射的转变.
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| 关 键 词： | 锥形激波 非均匀汇聚 内转式进气道 来流攻角 椭圆入口 |
| 收稿时间： | 2020-06-18 |
Non-Uniform Intensification Behaviors of a Converging Conical Shock Wave |
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| Affiliation: | University of Science and Technology of China, Hefei 230027, China |
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| Abstract: | Two non-perfect converging conical shock wave models, one with angle of attack and the other with ovality, were proposed to investigate the different behaviors of conical shock wave convergence with a deviation from the perfect axisymmetric condition. The investigation was carried out by using experimental observation in shock tunnel and numerical simulation. The results show that the circumferential non-uniformity in shock intensity caused by the angle of attack is enlarged due to the flow convergence, which results in remarkable differences between the windward and the leeward sides. The greater the angle of attack is, the stronger the non-uniformity of the shock intensity is, and the more likely the shock front becomes discontinuous with formation of kinks during the converging process. The convergence of the shock is weakened after the appearance of the kinks. On the other hand, the initial geometric non-uniformity of the shock caused by the constraint of ellipse exhibits a different behavior of shock intensification particularly between the direction of the major axis and the minor axis. The intensity of the shock increases faster along the major axis direction. The larger the aspect ratio of the ellipse is, the stronger the geometric non-uniformity of the initial shock is. During the converging process, the difference of shock intensity between the major and minor axes becomes more prominent, and more likely the shock front grows to form discontinuous kinks. The present research on the two models demonstrates that the inevitable occurrence of Mach reflection at the center will disappear and regular reflection shows up instead with a sufficient deviation from the perfect axisymmetric condition. |
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