Dynamic response of vortex breakdown flows to a pitching double-delta wing
Dynamic response of vortex breakdown flows to a pitching double-delta wing
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俯仰双三角翼涡破裂流的动态响应
DOI：
10.1016/j.ast.2017.10.008
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发表时间：
2018
影响因子：
5.6
通讯作者：
Zhixiang Xiao
中科院分区：
文献类型：
--
作者：
Jian Liu;Kunyu Luo;Haisheng Sun;Yong Huang;Zhitao Liu;Zhixiang Xiao
采用基于有限体积法的刚性移动网格和延迟分离涡模拟（DDES）技术，研究了80 °/65 °双三角翼（DDW）在正弦俯仰运动下的非定常绕流。重点集中在理解的行为的爆发点（BP），螺旋模式的不稳定性，压力波动，和动态俯仰稳定性。详细分析了约化频率（RF）在上述特征响应中的作用。与以往的实验结果一致，BP的运动近似为简谐运动，与俯仰运动的频率锁定，并伴随有受射频影响较大的相位滞后。结果表明，在后击穿区的时间平均流近似为锥形流，其锥角也取决于RF。在迎角为36 °的定常状态下，BP振荡的固有频率是临界频率，它决定了动态俯仰导数的符号。找到了一对临界频率，将BP、螺旋结构锥角和动态俯仰稳定性的特性划分为几个线性区段。提出了两种简化的一阶和二阶微分模型，并将其应用于BP的动态特性预测，二阶模型在一定范围内可以给出与目前计算流体力学（CFD）结果相吻合的滞回曲线。
A finite volume-based solver with rigid moving mesh and delayed detached eddy simulation (DDES) techniques is implemented to investigate the unsteady flows around an 80°/65° double-delta wing (DDW) subjected to sinusoidal pitching motions. The focus concentrates on understanding the behaviour of the burst point (BP), helical mode instability, pressure fluctuations, and dynamic pitching stability. The role of the reduced frequency (RF) in the response of the above features is analyzed in detail. It is in consistence with the previous experiments that the movement of the BP is nearly a simple harmonic motion and locked with the frequency of the pitching motion accompanied with a phase lag that is strongly affected by the RF. It is found that the time-averaged flow in the post-breakdown regions is approximately a conical flow, whose cone angle also depends on the RF. The natural frequency of BP oscillation at the stationary state of AOA = 36° is the critical frequency, which determines the sign of dynamic pitching derivative. A pair of critical frequencies is found, by which the features of the BP, cone angle of the helical structures, and dynamic pitching stability are divided into several linear sections. Two simplified 1st and 2nd order differential models are proposed and applied for predicting the dynamic behaviour of the BP, and the 2nd order model can give coincident hysteresis loops with the present computational fluid dynamics (CFD) results in a certain range.
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