This paper presents a numerical framework to study the interaction of isotropic turbulence with airfoils. Specifically, the developed numerical framework is used to investigate the distortion of the turbulent structures interacting with an airfoil’s leading edge. For turbulence modeling, Large Eddy Simulation (LES) is used. The isotropic turbulent inflow for the Computational Fluid Dynamics (CFD) simulations is synthetically generated using the turbulent digital filter method. The case studied with the numerical framework is a NACA 0012 airfoil with a chord-based Reynolds number of and an angle of attack of . The numerical simulation results are compared to high-speed particle image velocimetry (PIV) measurements performed for a NACA 0012 airfoil at the equivalent chord-based Reynolds number and turbulent inflow conditions. The CFD results of the numerical framework compare well with the experiments in terms of velocity spectra and RMS values upstream of the airfoil’s leading edge. The spectra and correlations of the velocity field generated by the turbulent digital filter demonstrate its ability to generate isotropic turbulent inflow. Instantaneous velocity fields show that the airfoil suppresses large-scale turbulent structures of the incoming turbulent flow. The size of the incoming turbulent structures decreases as they approach the leading edge due to the presence of the airfoil. The pre-multiplied spectra of the different velocity components show that downstream of the airfoil’s leading edge, the turbulent structures are stretched in the streamwise direction. The streamwise turbulent integral length scales and the velocity RMS values upstream of the airfoil’s leading edge indicate that the velocity components most affected by distortion are the streamwise and wall-normal components.

中文翻译：

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研究与翼型前缘相互作用的各向同性湍流流入的数值框架

本文提出了一个研究各向同性湍流与翼型相互作用的数值框架。具体来说，开发的数值框架用于研究与机翼前缘相互作用的湍流结构的变形。对于湍流建模，使用大涡模拟 (LES)。用于计算流体动力学 (CFD) 模拟的各向同性湍流流入是使用湍流数字滤波器方法综合生成的。使用数值框架研究的案例是 NACA 0012 翼型，其弦基雷诺数为 ，攻角为 。将数值模拟结果与在等效弦雷诺数和湍流流入条件下对 NACA 0012 翼型进行的高速粒子图像测速 (PIV) 测量进行比较。数值框架的 CFD 结果在翼型前缘上游的速度谱和 RMS 值方面与实验结果吻合良好。湍流数字滤波器生成的速度场的频谱和相关性证明了其生成各向同性湍流流入的能力。瞬时速度场表明翼型抑制了传入湍流的大规模湍流结构。由于翼型的存在，进入的湍流结构的尺寸随着它们接近前缘而减小。不同速度分量的预乘谱表明，在翼型前缘的下游，湍流结构在流向方向上被拉伸。翼型前缘上游的流向湍流积分长度尺度和速度 RMS 值表明，受畸变影响最大的速度分量是流向和壁法向分量。