The turbulent separated flow over an equilateral triangular cylinder at a Reynolds number 45000 (based on the triangle edge) is studied by means of large-eddy simulation (LES). The moderate Reynolds number is chosen in order to replicate available experimental data (Laser Doppler Anemometry measurements at the Volvo test rig). The OpenFoam CFD toolbox is used for the present numerical simulations. Several algebraic subgrid scale (SGS) closures, including the conventional Smagorinsky model ($C_s=0.1$ and $C_s=0.053$), the model by Vreman ($C_s=0.1$) and the dynamic version of the k-equation model are investigated. The spectral analysis of the vortex shedding and the convective instabilities as well as the turbulence kinetic energy dissipation rate is presented. Some aspects of the blockage effects are investigated and compared to experimental data available in the literature. It was shown that blockage affects significantly the mean drag and pressure coefficients of the triangular cylinder. At the same time the mean velocity field is tending to similarity. Overall, all SGS models reproduced most important aspects of the flow physics of the separated bluff-body flow, including integral flow parameters and spectral characteristics with dispersion about $10\text{\%}$, showing a reasonable consistency with the experimental data.

通过大涡模拟（LES）研究了雷诺数为45000（基于三角形边缘）的等边三角形圆柱体上的湍流分离流。选择适当的雷诺数是为了复制可用的实验数据（沃尔沃试验台上的激光多普勒风速测量）。OpenFoam CFD工具箱用于当前的数值模拟。几个代数子网格规模（SGS）闭包，包括常规的Smagorinsky模型（$C_s=0.1$ 和 $C_s=0.053$），由Vreman（$C_s=0.1$）和k方程模型的动态版本。给出了涡旋脱落，对流不稳定性以及湍流动能耗散率的频谱分析。研究了堵塞效应的某些方面，并将其与文献中提供的实验数据进行了比较。结果表明，阻塞显着影响三角形圆柱体的平均阻力和压力系数。同时，平均速度场趋于相似。总体而言，所有SGS模型都重现了分离的钝体流的流物理学的最重要方面，包括积分流参数和频谱特征，以及$10\text{％}$，与实验数据显示出合理的一致性。