Vortex dynamics around pitching plates
Vortex dynamics around pitching plates
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DOI：
10.1063/1.4879035
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发表时间：
2014-05
影响因子：
4.6
通讯作者：
Ryan Jantzen;K. Taira;Kenneth Granlund;M. Ol
中科院分区：
文献类型：
--
作者：
Ryan Jantzen;K. Taira;Kenneth Granlund;M. Ol
本文采用直接数值模拟和水洞实验相结合的方法，研究了矩形展弦比为2和4的平板和二维平板在自由来流中产生的尾迹涡动力学特性。尾涡组成的尖端，前缘和后缘涡的演变进行了比较与力的历史范围内的俯仰率。板绕其前缘以从π/8到π/48的减小的频率枢转，这对应于在1到6个弦长的行程上俯仰。尽管雷诺数相差很大，但计算结果与实验结果吻合较好。计算表明，翼尖效应最初局限在翼尖附近，但随着平板运动的进行，开始对前缘涡产生强烈影响，并伴随着对升力和阻力历史的影响。基于折合频率的比例关系被证明是在各种俯仰角速度下气动力历史的崩溃。
Vortex dynamics of wakes generated by rectangular aspect-ratio 2 and 4 and two-dimensional pitching flat plates in free stream are examined with direct numerical simulation and water tunnel experiments. Evolution of wake vortices comprised of tip, leading-edge, and trailing-edge vortices is compared with force history for a range of pitch rates. The plate pivots about its leading edge with reduced frequency from π/8 to π/48, which corresponds to pitching over 1 to 6 chord lengths of travel. Computations have reasonable agreement with experiments, despite large differences in Reynolds number. Computations show that the tip effects are confined initially near the wing tips, but begin to strongly affect the leading-edge vortex as the motion of the plate proceeds, with concomitant effects on lift and drag history. Scaling relations based on reduced frequency are shown to collapse aerodynamic force history for the various pitch rates.