Linear-stability-theory-based [ ] method plays an important role in boundary-layer transition prediction of aeronautical flows. Based on the simplification of linear stability theory (Drela and Giles, AIAA J, 1987), the amplification factor transport (AFT) equation for Tollmien–Schlichting waves using local variables was first proposed in 2013 (Coder and Maughmer, AIAA J, 2014). However, in transonic high-Reynolds-number flows, the AFT model seriously overestimates the value of [ ]. To fix this problem, we have conducted many linear stability analyses to rebuild the formulations of AFT model. Compressibility effect, which has a significant impact on the prediction of [ ] value, has been considered in the improved version. Coupled with the [ ] model for crossflow instabilities (Xu et al., CJA, 2020), the improved AFT model is established for transonic boundary layers. Several classic test cases are successfully employed to validate present AFT model, including a flat plate, an airfoil, an infinite swept wing, a sickled-shape wing, a 6:1 inclined prolate spheroid, the NASA Common Research Model, and ARA Transonic Swept Wing. Our prediction results show that both Tollmien–Schlichting instabilities and stationary crossflow instabilities can be captured and predicted well by the improved [ ] model in subsonic and transonic boundary layers.

A single-point transition closure model that incorporates analytical results by stability theory in a reasonably wide range of Mach numbers has been formulated for supersonic/hypersonic boundary-la...

A new computational fluid dynamics compatible transition model for the natural transition and laminar separation bubble induced transition is established using two transport equations with consideration of analysis results through linear stability theory linear stability theory. One transport equation is introduced to describe the growth of the laminar kinetic energy in the boundary layer. In addition, another transport equation of intermittency factor is built to trigger the transition by controlling the source term of turbulent kinetic energy equation. Finally, applying the two transport equations to a shear stress transport turbulence model completes a four-equation transition turbulence model. Comparisons of predictions using the new model with wind-tunnel experiments of the Schubauer and Klebanoff flat plate, S809 airfoil, Aerospatiale-A airfoil, and DLR-F5 wing validate the predictive qualities of the new transition turbulence model.

A computational fluid dynamics (CFD) compatible and fully local transition closure model is proposed for three-dimensional hypersonic boundary layers considering crossflow effects. The transition m...