Modified One-Equation Transition Model with Reduced Grid Sensitivity

Correlation-based transition transport models are widely used in Reynolds-averaged Navier–Stokes (RANS) simulations to predict laminar–turbulent transition. However, it is observed that some of these models exhibit dependency on the initial flow conditions and may not respond adequately to time-varying flowfields in unsteady computations, especially on coarser grids. The present work introduces a modification to the intermittency transport equation to address these limitations. The modified formulation is first assessed using canonical steady-state test cases covering a wide range of Reynolds numbers. The results demonstrate that the modified formulation significantly reduces the sensitivity of the model to the initial conditions and improves the consistency of the predicted transition location. The approach is then applied to two unsteady test cases. In these simulations, the modified model demonstrates an improved ability to adapt the intermittency field in response to changes in the flowfield, leading to a behavior that is more consistent with the underlying transition criterion, particularly on coarser grids.