The goal of this work was to quantify the uncertainty and sensitivity of commonly used turbulence models in Reynolds-Averaged Navier-Stokes codes due to uncertainty in the values of closure coefficients for transonic, wall-bounded flows and to rank the contribution of each coefficient to uncertainty in various output flow quantities of interest. Specifically, uncertainty quantification of turbulence model closure coefficients was performed for transonic flow over an axisymmetric bump at zero degrees angle of attack and the RAE 2822 transonic airfoil at a lift coefficient of 0.744. Three turbulence models were considered: the Spalart-Allmaras Model, Wilcox (2006) k-w Model, and the Menter Shear-Stress Trans- port Model. The FUN3D code developed by NASA Langley Research Center was used as the flow solver. The uncertainty quantification analysis employed stochastic expansions based on non-intrusive polynomial chaos as an efficient means of uncertainty propagation. Several integrated and point-quantities are considered as uncertain outputs for both CFD problems. All closure coefficients were treated as epistemic uncertain variables represented with intervals. Sobol indices were used to rank the relative contributions of each closure coefficient to the total uncertainty in the output quantities of interest. This study identified a number of closure coefficients for each turbulence model for which more information will reduce the amount of uncertainty in the output significantly for transonic, wall-bounded flows.
展开▼
机译：这项工作的目标是量化由于跨音，壁界流动的闭合系数的值的不确定性而在雷诺瓦斯平均的Navier-Stokes代码中的常用湍流模型的不确定度和敏感性，并对每个系数的贡献进行排名各种输出流量的不确定性。具体地，在零度攻角处的轴对称凸块上进行跨音流动的跨音流动进行湍流模型闭合系数的不确定度量，并且在升力系数为0.744的升降系数下延长凸起的延长凸块。考虑了三种湍流模型：Spalart-Allmaras模型，Wilcox（2006）K-W型号，以及导师剪切应力转换模型。 NASA Langley Research Center开发的Fun3D代码用作流动求解器。不确定性定量分析采用基于非侵入式多项式混沌的随机扩展作为一种有效的不确定繁殖方法。几种集成和点数量被认为是CFD问题的不确定输出。所有闭合系数都被视为以间隔表示的认识不确定变量。 SOBOL指数用于将每个闭合系数的相对贡献与产出量的产出量中的总不确定性进行排名。该研究确定了每个湍流模型的许多闭合系数，因为该湍流模型对于该湍流模型，更多信息将在显着为跨音，壁限流的输出中的不确定性量减少。
展开▼
