Assessment and Grid Convergence Study of RANS-Based Transition Models for High-Speed Flows

Accurate modeling of laminar-to-turbulent transition is crucial for the design of hypersonic flight systems. However, the current transition models used in production CFD codes are insufficient for high-speed flows. Many extensions to low-speed models have been suggested; however, a thorough verification and validation effort is needed before these models can be used in design settings. A meaningful assessment of the generalization capability of these models is also hindered by a lack of information regarding the specific flow configurations and grids employed for model calibration. In this work, we present an independent assessment of two models for high-speed transition, namely, a one-equation model within the shear-stress-transport [Formula: see text] framework and a two-equation model based on the [Formula: see text] equations. These models are implemented in the NASA OVERFLOW 2.3e solver, and a thorough description of the models, numerical parameters, and coupled turbulence modeling parameters is given. Additionally, a formal grid convergence study is conducted for six test cases, covering first-mode and second-mode transitions, such that grid-independent predictions for each model for each case are found. These contributions represent a critical step in the characterization of the models and provide a basis for future users to verify their predictions.