Abstract Indented surface grooves can eliminate the laminar separation bubbles formed on airfoil surfaces, and thus have the potential to improve the aerodynamic performance of small wind turbines. In this study, a three-equation transitional turbulence model was selected and validated with experimental data to simulate the 2D flow around a NACA 4415 airfoil. Parametric simulation of surface groove characteristics was then conducted to investigate their effects on aerodynamic behavior. It was found that the recess depth ratio ( h / δ , h: groove recess depth, δ: baseline boundary layer thickness) is the key influencing factor among the groove feature parameters, with the most effective value between h / δ = 1.0 and 1.5. A smaller aspect ratio of recess depth to groove width is required to trap the vortex for a shallow recess depth, while a higher aspect ratio can stabilize the vortex for a deep recess. The endpoint of a groove can affect the potential vortex size within it, and the optimum endpoint is located around 0.16 c (c: airfoil chord). Moreover, a rectangular groove especially for a recess depth ratio h / δ = 1.2 − 1.5 offers better aerodynamic performance than an arc groove, as the rectangular configuration more efficiently restricts the flow motion inside the groove.

中文翻译：

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表面凹槽对NACA 4415小型风力机翼型气动性能影响的数值研究

摘要 锯齿状表面凹槽可以消除翼型表面形成的层流分离气泡，具有提高小型风力机气动性能的潜力。在这项研究中，选择了一个三方程过渡湍流模型并用实验数据进行了验证，以模拟 NACA 4415 翼型周围的二维流动。然后进行表面凹槽特性的参数模拟，以研究它们对空气动力学行为的影响。发现凹槽深度比（h/δ，h：凹槽凹槽深度，δ：基线边界层厚度）是凹槽特征参数中的关键影响因素，在h/δ=1.0和1.5之间最有效. 需要较小的凹槽深度与凹槽宽度的纵横比来捕获浅凹槽深度的涡流，而更高的纵横比可以稳定深凹处的涡流。凹槽的端点会影响其中的潜在涡流大小，最佳端点位于 0.16 c（c：翼型弦）附近。此外，矩形凹槽特别是凹槽深度比 h / δ = 1.2 - 1.5 比弧形凹槽提供更好的空气动力学性能，因为矩形配置更有效地限制凹槽内的流动运动。