A CFD-compatible transition model using an amplification factor transport equation

A new laminar-turbulent transition model for low-turbulence external aerodynamic applications is developed that incorporates linear stability theory in a manner compatible with modern CFD solvers. The model utilizes a new transport equation that describes the growth of the maximum instability amplitude in the presence of a boundary layer. To avoid the need for integration paths and non-local operations, a locally-defined non-dimensional pressure gradient parameter is utilized that serves as an estimator of the integral boundary-layer properties. The model has been implemented into the OVERFLOW 2.2e solver. Comparisons of predictions using the new model with high-quality, wind-tunnel measurements of airfoil section characteristics confirm the predictive qualities of the model, as well as its improvement over the current state of the art in CFD transition modeling.