Synthetic (zero net mass flux) jets are an active flow control technique to manipulate the flow field in wall-bounded and free-shear flows. The present paper focuses on the role of the periodic actuation mechanisms on the boundary layer of a SD7003 airfoil at $$Re=U_{\infty } C/\nu =6\times 10^4$$ . Here, Reynolds number is defined in terms of the free-stream velocity $$U_{\infty }$$ and the airfoil chord C. The actuation is applied near the leading edge of the airfoil and is periodic in time and in the spanwise direction. The actuation successfully eliminates the laminar bubble at $$AoA=4^{\circ }$$ , however, it does not produce an increase in the airfoil aerodynamic efficiency. At angles of attack larger than the point of maximum lift, the actuation eliminates the massive flow separation, the flow being attached to the airfoil surface in a significant part of the airfoil chord. As a consequence, airfoil aerodynamic efficiency increases by a 124% with a reduction of the drag coefficient about 46%. This kind of technique seems to be promising at delaying flow separation and its associated losses when the angle of attack increases beyond the maximum lift for the baseline case.

中文翻译：

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在雷诺数 Re = 60000 时，驱动对翼型边界层的影响

合成（零净质量通量）射流是一种主动流动控制技术，用于操纵壁限流和自由剪切流中的流场。本文重点研究了周期性驱动机制在 $$Re=U_{\infty } C/\nu =6\times 10^4$$ 处的 SD7003 翼型边界层上的作用。在这里，雷诺数是根据自由流速度 $$U_{\infty }$$ 和翼型弦 C 定义的。 驱动施加在翼型前缘附近，并且在时间和展向方向上是周期性的. 驱动成功地消除了 $$AoA=4^{\circ }$$ 处的层流气泡，但是，它不会增加翼型空气动力学效率。在攻角大于最大升力点时，驱动消除了大量流动分离，气流在翼型弦的重要部分附着在翼型表面上。因此，翼型空气动力学效率提高了 124%，阻力系数降低了约 46%。当攻角增加超过基线情况的最大升力时，这种技术似乎有希望延迟流动分离及其相关损失。