Large-eddy simulation of low-Reynolds-number flow around partially porous airfoils

J. Li, K. Nagata, T. Watanabe 
Large-eddy simulation of low-Reynolds-number flow around partially porous airfoils 
Journal of Aircraft, 60 1-12 2023

This article may be found at https://doi.org/10.2514/1.C037253.

Accepted manuscript is available here. 
This version is free to view and download for private research and study only. 

Abstract

This paper uses the large-eddy simulation framework in OpenFOAM to investigate the flow characteristics around two-dimensional partially porous airfoils with symmetrical flat geometries, which were used in a previous experiment. The effects of a porous medium near the trailing edge are investigated at a chord Reynolds number of 350,000. Two porous media are modeled to investigate how the porous medium influences the flow around the airfoil and aerodynamic performance: One is a normal porous medium, defined as a homogeneous and isotropic material with identical properties in all directions. The other medium consists of straight holes perpendicular to the airfoil surface, allowing fluid to pass through unidirectionally. It is observed that drag and lift forces vary, depending on the internal structure of the porous medium. The size of the laminar separation bubbles also varies, depending on the parameters of the porous medium, such as the internal structure, the length of the porous section, and the porosity. It is shown that an airfoil with a low-porosity unidirectional porous medium increases the lift-to-drag ratio at high angles of attack as compared with the nonporous airfoil.

日本語訳 (DeepL翻訳)

部分的に多孔質構造を持つ翼周りの低レイノルズ数流れのLarge-Eddy Simulation

本論文では,OpenFOAM のラージ・エディ・シミュレーショ ンの手法を用いて,以前の実験で使用した対称平板形状の 2 次元一部多孔質翼周りの流れ特性を調査した.後縁近傍の多孔質媒体の影響を、翼弦レイノルズ数350,000で調べた。多孔質媒体が翼形周りの流れと空力性能にどのような影響を与えるかを調べるために、2つの多孔質媒体をモデル化した: 1つは通常の多孔質媒体で、すべての方向に同一の特性を持つ均質で等方性の材料として定義される。もう1つの多孔質媒体は、翼形表面に垂直な直線状の穴からなり、流体が一方向に通過する。多孔質媒体の内部構造によって、抗力と揚力が変化することが観察された。層流分離気泡の大きさも、多孔質媒体の内部構造、多孔質断面の長さ、気孔率などのパラメータによって変化する。低空隙率の一方向多孔質媒体を用いた翼型は、非多孔質翼型と比較して、高迎角における揚力対抗力比が増加することが示された。