Abstract Laminarization of a turbulent flow due to wall heating has been known for more than 50 years, to the point that it is sometimes used as means of reducing friction. However this phenomenon has been mainly studied for cylindrical pipes and with imposed heat flux but not for channel flows and with imposed temperature boundary conditions, especially with asymmetric ones (that is to say in presence of a transverse thermal gradient). Based on the recent success of some Reynolds-averaged Navier-Stokes (RANS) models to correctly describe the influence of a strong transverse temperature gradient on turbulent Poiseuille flows, when compared to similar direct numerical simulations (DNS) or large eddy simulations (LES) results, these approaches are used here to investigate reverse transition. Since the choice of the turbulence model has a non-negligible influence on the results, however, it is necessary to use different models to get an indication of the uncertainty associated with them. The proposed methodology is based on the use of RANS closures that do not involve any wall functions due to the strong gradient in the wall layer that has to be modeled. Thus, two first-moment closures and a second-moment closure are considered: the k − ω − SST and the k − e − v 2 ¯ / k , and the EB-RSM. The latter two rely on an elliptic blending. The turbulent heat flux is modeled with a simple gradient diffusion hypothesis (SGDH) and a generalized gradient diffusion hypothesis (GGDH) for the first-moment and second-moment closures respectively. In summary, more than 800 calculations are performed for the above three models in order to analyze the reverse transition, and to open room for debate on the possibility for such approaches to correctly reproduce the experimentally observed behavior.

中文翻译：

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由于温度梯度，内部湍流通道流动中的不对称反向转变现象

摘要 由于壁面加热引起的湍流层化已经为人所知 50 多年，以至于它有时被用作减少摩擦的手段。然而，这种现象主要针对圆柱形管道和施加的热通量进行了研究，而不是针对通道流动和施加的温度边界条件，尤其是不对称的（即存在横向热梯度）。与类似的直接数值模拟 (DNS) 或大涡模拟 (LES) 相比，一些雷诺平均纳维-斯托克斯 (RANS) 模型最近成功地正确描​​述了强横向温度梯度对湍流泊肃叶流的影响结果，这里使用这些方法来研究反向转换。然而，由于湍流模型的选择对结果有不可忽略的影响，因此有必要使用不同的模型来指示与它们相关的不确定性。所提出的方法基于使用 RANS 闭包，由于必须建模的壁层中的强梯度，该闭包不涉及任何壁函数。因此，考虑了两个第一时刻闭包和第二时刻闭包：k − ω − SST 和 k − e − v 2 ¯ / k ，以及 EB-RSM。后两者依赖于椭圆混合。湍流热通量分别使用简单梯度扩散假设 (SGDH) 和广义梯度扩散假设 (GGDH) 建模，分别用于第一时刻和第二时刻闭包。总之，