A New Extension of Wray-Agarwal Wall Distance Free Turbulence Model to Rough Wall Flows

This paper provides a roughness correction to the latest version of Wall-Distance-Free Wray-Agarwal (WA) one equation turbulence model (WA2018). The results from WA 2018 rough wall model are compared to Spalart-Allmaras model and the previous version of WA roughness model (WA2017). The results from WA2018-Rough model for flow over a flat plate show substantial improvement from the previous version WA2017-Rough and a good agreement with a semi-empirical formula based on experimental results. For flow past a S809 airfoil with surface roughness, WA2018-Rough model performs quite well compared to SA-Rough model

Application of Quadratic Constitutive Relation to One- Equation k-kL Turbulence Model

This paper analyzes the accuracy of the recently developed one-equation k-kL turbulence model with Quadratic Constitutive Relation (QCR) compared to the linear Boussinesq relation and Algebraic Reynolds Stress Model (ARSM). The computational results in several benchmark cases from NASA TMR are compared to other widely used one equation turbulence models with QCR, such as Spalart-Allmaras model (SA), Wray-Agarwal model (WA) and SST k-ω model. In particular, one-equation k-kL-QCR model shows good accuracy with experimental data for supersonic flow in a square duct where the effect of QCR is clearly visible in capturing the secondary flow vortices which is not feasible with the any standard model without QCR. In addition, both one-equation k-kL and one-equation k- kL-QCR models show better accuracy for subsonic separated flow in 3D NASA Glenn S- duct compared to other one-equation models. Other test cases show little difference in the results obtained without and with QCR

Investigation of Turbulence Model Uncertainty for Supersonic/Hypersonic Shock Wave-Boundary Layer Interaction Predictions

The purpose of this paper is to present the results of an uncertainty and sensitivity analysis study for commonly used turbulence models in Reynolds-Averaged Navier-Stokes codes due to the epistemic uncertainty in closure coeficients for selected supersonic and hypersonic shock wave-turbulent boundary layer interaction problems that are of interest to the turbulence modeling community. The CFD cases studied include: (1) a turbulence model validation case consisting of an axisymmetric cylindrical body with a trailing edge are of 20 degrees at an upstream Mach number of 7.11, and (2) an axisymmetric shock wave boundary layer interaction case with a trailing edge are of 30 degrees at Mach = 2.85 that is of interest in the NASA\u27s 40% Challenge and CFD Prediction Error Assessment Workshop. Two turbulence models are investigated: the Spalart-Allmaras Model and the Wilcox (2006) k-ω Model. The flow solver used in the study is FUN3D, a code developed by NASA Langley Research Center. The uncertainty quantification approach involves stochastic expansions based on non-intrusive polynomial chaos to effciently propagate the uncertainty. All closure coeficients are treated as epistemic uncertain variables. Sobol indices are used to rank the relative contribution of each closure coeficient to the total uncertainty for several output flow quantities. The results of the current study generalize the findings of a previously conducted study on shock wave-turbulent boundary layer interactions and identify a set of closure coeficients for each turbulence model which contribute most to the uncertainty in various output quantities of interest