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| 1 | Numerical investigations of the transient cavitating vortical flow structures over a flexible NACA66 hydrofoil显示文摘In this paper,the cavitating flow over a flexible NACA66 hydrofoil is studied numerically by a modified fluid-structure interaction strategy with particular emphasis on understanding the flow-induced vibration and the cavitating vortical flow structures.The modified coupling approaches include(1)the hydrodynamic solution obtained by the large eddy simulation(LES)together with a homogenous cavitation model,(2)the structural deformation solved with a cantilever beam equation,(3)fluid-structural interpolation and volume mesh motion based on the radial basis functions and greedy algorithm.For the flexible hydrofoil,the dominant flow-induced vibration frequency is twice of the cavity shedding frequency.The cavity shedding frequency is same for the rigid and flexible hydrofoils,demonstrating that the structure vibration is not large enough to affect the cavitation evolution.The predicted cavitating behaviors are strongly three-dimensional,that is,the cavity is(a)of a triangular shape near the hydrofoil tip,(b)of a rectangular shape near the hydrofoil root,and(c)with a strong unsteadiness in the middle of the span,including the attached cavity growth,oscillation and shrinkage,break-off and collapse downstream.The unsteady hydroelastic response would strongly affect the cavitation shedding process with small-scale fragments at the cavity rear part.Furthermore,three vortex identification methods(i.e.,the vorticity,the Q-criteria and the Ω method)are adopted to investigate the cavitating vortex structures around the flexible hydrofoil.It is indicated that the cavity variation trend is consistent with the vortex evolution.The vortex structures are distributed near the foil trailing edge and in the cavitation region,especially at the cavity-liquid interface.With the transporting downstream the shedding cavities,the vortices gradually increase in the wake flows. | Ren-fang Huang Te-zhuan Du Yi-wei Wang Cheng-guang Huang | 2020 | Journal of Hydrodynamics2020，32，5： | 4 |
| 2 | 反向喷流对运载火箭返回段气动特性影响研究显示文摘为了准确获取发动机反向喷流干扰下运载火箭返回段全箭及栅格舵气动特性,设计缩比试验模型及地面喷流模拟系统,采用高速纹影、全箭及栅格舵部件测力等测试方法,开展反向喷流状态下风洞试验研究。结果表明:发动机工作时反向喷流与头部弓形激波相互干扰,改变全箭绕流流场分布特征,使得一子级返回段的轴向力系数减小,对一子级返回段的法向力系数和俯仰力矩系数影响规律与来流马赫数有关,影响量与喷流强度和攻角等相关;反向喷流干扰使得栅格舵的控制舵效整体呈降低趋势,在高马赫数来流下甚至会导致控制特性反向。通过反向喷流测力风洞试验,有效指导和开展返回段精细化气动设计,为我国重复使用运载火箭的工程实现提供技术参考。 | 程川 刘阳 王吉飞 崔村燕 朱雄峰 | 2023 | 宇航学报2023，44，3： | 1 |
| 3 | 绕弹性水翼空化流动及其流激振动特性研究显示文摘该文采用基于径向基函数的流固耦合方法,对不同空化数下绕刚性水翼/弹性水翼的空泡形态及其流激振动特性进行了数值模拟。结果表明,绕弹性水翼空泡形态具有三个典型特征:(1)靠近翼尖前缘的附着空泡形态为三角形;(2)翼尖出现梢涡空化,梢涡空化随着空化数的降低而逐渐明显;(3)回射流作用下水翼存在云状空泡的周期性脱落。对不同空化数下弹性水翼的振动特性进行分析发现,随着空化数的下降,水翼振动的平均振幅及振幅波动值先增大再减小,平均振幅和振幅波动由大到小依次是:云空化>超空化>片空化。 | 丘润荻 支玉昌 张珍 黄仁芳 王一伟 杜特专 | 2022 | 水动力学研究与进展(A辑)2022，37，2： | 0 |
| 4 | 地效翼的颤振特性研究显示文摘地面效应是指当机翼贴近地面飞行时,由于受到地面的干扰作用而引起升力增加和阻力降低的现象。研究地面效应对颤振的影响规律。建立基于计算流体力学/计算结构力学耦合的颤振计算方法,采用标模AGARD 445.6机翼对颤振计算方法进行验证。在此基础上,以贴近地面的三维机翼为研究对象开展颤振分析,研究指出地面效应增强了非定常气动力的幅值,而且离地越近这种效果就越明显,从而导致颤振速度随着离地高度的降低而减小。然后重点讨论了攻角对地效翼颤振的影响,与不考虑地效的经典线性颤振理论不同,指出地效翼的颤振速度与攻角有关,在地效区域内,增加机翼的攻角会使发生颤振时的静变形变大,导致机翼抬起和离地高度增加,地效减弱,使得颤振速度随攻角的增大而提高。 | 赵奥博 郑冠男 黄程德 杨国伟 陈玮琪 | 2023 | 振动与冲击2023，42，17： | 0 |
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