In this study, the effect of cutting the end of a thick airfoil and adding a cavity on its flow pattern is studied experimentally using PIV technique. First, by cutting 30% chord length of the Riso airfoil, a thick blunt trialing-edge airfoil is generated. The velocity field around the original airfoil and the new airfoil is measured by PIV technique and compared with each other. Then, adding two parallel plates to the end of the new airfoil forms the desired cavity. Continuous measurement of unsteady flow velocity over the Riso airfoil with thick blunt trailing edge and base cavity is the most important innovation of this research. The results show that cutting off the end of the airfoil decreases the wake region behind the airfoil, when separation occurs. Moreover, adding a cavity to the end of the thickened airfoil causes an increase in momentum and a further decrease in the wake behind the trailing edge that leads to a drag reduction in comparison with the thickened airfoil without cavity. Furthermore, using cavity decreases the Strouhal number and vortex shedding frequency.Graphical abstract

中文翻译：

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使用 PIV 技术在低雷诺数下具有基腔的厚钝后缘机翼上的流动可视化

在这项研究中，使用 PIV 技术通过实验研究了切割厚翼型的末端并添加腔对其流动模式的影响。首先，通过切割 Riso 翼型的 30% 弦长，生成厚钝的试验边缘翼型。原翼型和新翼型周围的速度场通过PIV技术测量并相互比较。然后，在新翼型的末端添加两个平行板形成所需的空腔。连续测量具有厚钝后缘和基腔的 Riso 翼型上的非定常流速是本研究最重要的创新。结果表明，当分离发生时，切断翼型的末端会减少翼型后面的尾流区域。而且，在加厚翼型的末端增加一个空腔会导致动量增加，后缘后面的尾流进一步减少，与没有空腔的加厚翼型相比，这导致阻力减小。此外，使用空腔会降低 Strouhal 数和涡旋脱落频率。 图形摘要