Numerous experimental and analytical studies have investigated corner flows, revealing symmetric flow characteristics and reduced turbulence production along the corner bisector. However, the underlying formation mechanisms of the flow characteristics have not been discussed. This study proposes that the reduction in turbulence production along the corner bisector is due to the cancellation of vortex motions originating independently from two orthogonal walls. Based on this insight, an elliptic relaxation function in the turbulence model was modified using OpenFOAM, an open-source computational fluid dynamics (CFD) code to reflect the geometric symmetry along the corner bisector. The modified turbulence model reproduced the reduced turbulence characteristics along the corner bisector, and the results were validated against the experimental data inside a rectangular duct under both isothermal and heating conditions. Our findings indicate that the modified turbulence model, by incorporating symmetry along the corner bisectors, accurately predicts the phenomena observed in the experiment under different thermal conditions. This demonstrates the practical applicability of this turbulence modeling approach in heat transfer analysis for rectangular ducts at a low cost.

中文翻译：

---

Phit-fk-ε模型中角流湍流特性及椭圆松弛函数修正

大量的实验和分析研究研究了角流，揭示了对称流特性并减少了沿角平分线产生的湍流。然而，流动特性的潜在形成机制尚未得到讨论。这项研究提出，沿着角平分线的湍流产生的减少是由于独立源自两个正交壁的涡流运动的抵消。基于这一见解，我们使用开源计算流体动力学 (CFD) 代码 OpenFOAM 修改了湍流模型中的椭圆松弛函数，以反映沿角平分线的几何对称性。修改后的湍流模型再现了沿角平分线的减少的湍流特性，并根据等温和加热条件下矩形管道内的实验数据对结果进行了验证。我们的研究结果表明，修改后的湍流模型通过结合沿角平分线的对称性，可以准确地预测在不同热条件下实验中观察到的现象。这证明了这种湍流建模方法在矩形管道传热分析中的低成本实际适用性。