The implementation of adaptive mesh refinement (AMR) in the spectral-element method code Nek5000 is used for the first time on the well-resolved large-eddy simulation of the turbulent flow over wings. In particular, the flow over a NACA4412 profile with a $$5^\circ$$ 5 ∘ angle of attack at chord-based Reynolds number $${\text {Re}}_c=200{,}000$$ Re c = 200 , 000 is analyzed in the present work and compared with a previous conformal simulation used as baseline. The mesh, starting from a coarse resolution, is progressively and automatically refined by means of AMR, which allows for high resolution near the wall and wake whereas significantly larger elements are used in the far-field. The resulting mesh, which remains unchanged in the production runs (i.e. AMR is used to create the final mesh, which is then fixed), is of higher resolution than those in previous conformal cases, and it allows for the use of larger computational domains, avoiding the use of precursor RANS simulations to determine the boundary conditions. This is achieved with, approximately, 2 times lower total number of grid points if the same spanwise length is used. Turbulence statistics obtained in the AMR simulation show good agreement with the ones obtained with the conformal mesh, and the pressure-coefficient distribution along the wing surface matches pressure-scan experimental data obtained in the MTL wind tunnel at KTH. The use of AMR is therefore expected to enable the simulation of high-Reynolds numbers turbulent flows over complex geometries (such as wings), thus allowing the study of pressure-gradient effects at high Reynolds numbers relevant for practical applications.

中文翻译：

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为机翼周围湍流的谱元模拟启用自适应网格细化

谱元方法代码 Nek5000 中自适应网格细化 (AMR) 的实现首次用于对机翼上的湍流进行良好解析的大涡模拟。特别是，在基于弦的雷诺数 $${\text {Re}}_c=200{,}000$$ Re c = 处，具有 $$5^\circ$$ 5 ∘ 攻角的 NACA4412 剖面上的流量200 , 000 在目前的工作中进行了分析，并与以前用作基线的保形模拟进行了比较。网格从粗分辨率开始，通过 AMR 逐渐自动细化，这允许在壁面和尾流附近实现高分辨率，而在远场中使用明显更大的单元。生成的网格在生产运行中保持不变（即 AMR 用于创建最终网格，然后固定），比以前的保形情况具有更高的分辨率，并且它允许使用更大的计算域，避免使用前体 RANS 模拟来确定边界条件。如果使用相同的展向长度，这可以通过大约 2 倍的网格点总数来实现。AMR 模拟中获得的湍流统计数据与共形网格获得的湍流统计数据非常吻合，沿机翼表面的压力系数分布与 KTH 的 MTL 风洞中获得的压力扫描实验数据相匹配。因此，AMR 的使用有望模拟复杂几何结构（例如机翼）上的高雷诺数湍流，从而允许研究与实际应用相关的高雷诺数下的压力梯度效应。