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arXiv 1711.09469physics.flu-dyn
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翼型分离控制中壁面法向和angular momentum喷射的影响

Effects of wall-normal and angular momentum injections in airfoil separation control

Phillip M. Munday, Kunihiko Taira

摘要:

本计算研究的目的是量化壁面法向和角动量注入对抑制规范翼型上的层流分离的影响。用大涡模拟研究了NACA 0012翼型在$α= 9^\circ$和$Re = 23,000$上完全分离不可压缩流动的开环控制。本研究借由模型边界条件,将壁面法向动量与角动量分别独立地导入旋转喷流的分离流中。详细研究了流场和表面涡量通量对驱动输入的各种组合的响应。据观察,除了角动量输入的壁面法向动量注入增强了流动分离的抑制。通过修改动量系数的标准定义,来表征壁面法向和角动量输入对升力增强和分离抑制的影响。通过引入基于无量纲旋流数的特征旋流射流速度,将角动量的影响纳入修正动量系数中。有了这个修正的动量系数,我们就能把每一个受控流分为分离流、过渡流和附着流。

英文摘要:

The objective of this computational study is to quantify the influence of wall-normal and angular momentum injections in suppressing laminar flow separation over a canonical airfoil. Open-loop control of fully separated, incompressible flow over a NACA 0012 airfoil at $α= 9^\circ$ and $Re = 23,000$ is examined with large-eddy simulations. This study independently introduces wall-normal momentum and angular momentum into the separated flow using swirling jets through model boundary conditions. The response of the flow field and the surface vorticity fluxes to various combinations of actuation inputs are examined in detail. It is observed that the addition of angular momentum input to wall-normal momentum injection enhances the suppression of flow separation. Lift enhancement and suppression of separation with the wall-normal and angular momentum inputs are characterized by modifying the standard definition of the coefficient of momentum. The effect of angular momentum is incorporated into the modified coefficient of momentum by introducing a characteristic swirling jet velocity based on the non-dimensional swirl number. With this single modified coefficient of momentum, we are able to categorize each controlled flow into separated, transitional, and attached flows.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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