Effects of aspect ratio and angle of attack on tip vortex structures and aerodynamic performance for rotating flat plates
Effects of aspect ratio and angle of attack on tip vortex structures and aerodynamic performance for rotating flat plates
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展弦比和攻角对旋转平板叶尖涡结构及气动性能的影响
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Bo Cheng
中科院分区：
文献类型：
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作者：
Chengyu Li;Haibo Dong;Bo Cheng
采用数值模拟的方法研究了低雷诺数区（200 ~ 1600）展弦比和攻角对旋转翼涡结构、环量和气动性能的影响。本文考虑了不同展弦比（1 ~ 8）的矩形机翼，其迎角范围为15 ~ 90 °。模拟进行了内部浸没边界法为基础的直接数值模拟（DNS）求解器。对涡形成的详细分析表明，翼尖附近的一般尾迹模式从单个涡环转变为一对反向旋转的涡环。叶尖涡的发展与LEV的强度有关。一般来说，较强的LEV将增强对应对后缘涡量。随着TEV的增加，在翼尖底角处形成二次翼尖涡，并产生一对反向旋转的翼尖涡环。随着雷诺数的增加，这些涡环会相互作用，在弧形涡环的尾部形成发夹状的旋涡结构。除涡结构外，还检查了气动载荷和功率消耗。研究结果可为进一步了解大迎角下有限展弦比旋转机翼的涡动力学提供参考。
Numerical simulations are used to investigate the effects of aspect ratio and angle of attack on the vortex structure, circulation and aerodynamic performance of revolving wings at a low Reynolds number regime (200 ~ 1600). Rectangular wings with various aspect ratio (1 ~ 8) are considered and rotating from rest at angle of attack ranging from 15 to 90 degrees. Simulations are carried out using an in-house immersed-boundary-method-based direct numerical simulation (DNS) solver. A detailed analysis of the vortex formation shows that the general wake pattern near the wingtip shift from a single vortex loop to a pair of counter-rotating vortex loops. This tip vortex evolution was found related to the strength of LEV. In general, the stronger LEV will enhance the counter-pair trailing-edge vorticity. As the TEV increased, a secondary tip vortex will be formed at the bottom corner of wingtip and generate a pair of counter-rotating tip vortex loops. With the increment of the Reynolds number, these vortex loops will interact with each other and form hairpin-like vortical structures in the tail of the arc-shaped vortex loops. In addition to the vortex structures, the aerodynamic loading and power consumption were also examined. The findings from this work could be used to further understand the vortex dynamics of finite-aspect-ratio revolving wings at high angle of attack.