Experimental evaluation of the flow field induced by an active vortex generator

IF 2.8 2区工程技术 Q2 ENGINEERING, MECHANICAL Experimental Thermal and Fluid Science Pub Date : 2024-08-05 DOI:10.1016/j.expthermflusci.2024.111280

Sen Wang, Bryce Horn, Findlay McCormick, Sina Ghaemi

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Abstract

This investigation examined the flow field generated by a ramp-shaped vortex generator (VG) that underwent active oscillation within a laminar boundary layer. The oscillations were applied through a servomotor, which pivoted the VG around its leading edge. The study evaluated the influence of varying the maximum VG height during the oscillations (h), actuation frequency (f), and the waveform governing the periodic oscillation of the VG. Planar particle image velocimetry (PIV) measurements were conducted to estimate flow mixing and the drag induced by the VG. The height-based Reynolds number (Re_h) ranged from 300 to 600, and the chord-based Strouhal number (St_c) for the oscillations varied from 0.67 to 3.33. The findings of the study indicate that active VGs lead to a greater wall-normal transport of streamwise momentum and result in lower drag compared to static VGs. Furthermore, increasing h results in larger momentum transport and drag of the active VGs. The investigation also revealed that the highest momentum transport and drag occurred when f was close to the instability frequency of the shear layer. The results show the potential of active VGs for separation control under various flow conditions.

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主动涡流发生器诱导流场的实验评估

这项研究考察了在层流边界层内进行主动振荡的斜坡形涡流发生器（VG）所产生的流场。振荡是通过伺服电机施加的，伺服电机使 VG 绕其前缘旋转。研究评估了改变振荡期间 VG 最大高度（h）、驱动频率（f）和 VG 周期性振荡波形的影响。进行了平面颗粒图像测速仪（PIV）测量，以估算流体混合和 VG 诱导的阻力。基于高度的雷诺数（Reh）从 300 到 600 不等，基于弦线的斯特劳哈尔数（Stc）从 0.67 到 3.33 不等。研究结果表明，与静态 VG 相比，主动 VG 会导致更大的流向动量的壁面法向传输，并导致更低的阻力。此外，增加 h 会导致主动 VG 的动量传输和阻力增大。研究还发现，当 f 接近剪切层的不稳定频率时，动量传输和阻力最大。研究结果表明，在各种流动条件下，主动 VG 都具有进行分离控制的潜力。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Experimental Thermal and Fluid Science 工程技术-工程：机械

CiteScore

6.70

自引率

3.10%

发文量

159

审稿时长

34 days

期刊介绍： Experimental Thermal and Fluid Science provides a forum for research emphasizing experimental work that enhances fundamental understanding of heat transfer, thermodynamics, and fluid mechanics. In addition to the principal areas of research, the journal covers research results in related fields, including combined heat and mass transfer, flows with phase transition, micro- and nano-scale systems, multiphase flow, combustion, radiative transfer, porous media, cryogenics, turbulence, and novel experimental techniques.