Applications of transition model based on amplification factor of stationary crossflow waves in transonic boundary layers

After nearly half a century’s research, it is known that the e^N method based on linear stability theory (LST) is one of the most reliable methods for the boundary layer transition prediction. However, the traditional LST is difficult to be applied to complex aerodynamic configurations due to its complicated process of searching for the solution. With the rapid development of local-variable-based transition models, it has become a research hotspot to model the analysis process of the traditional LST, that is, to transform the LST analysis into a computational fluid dynamics (CFD) problem. After Coder & Maughmer developed the transport equation for the amplification factor of two-dimensional Tollmien-Schlichting (T-S) waves, the amplification factor transport equation for stationary crossflow waves in incompressible boundary layers was first proposed in 2019 and then extended to transonic flows in 2020 by the present authors. In this study, a wind-tunnel test model that only targets the crossflow transition of a transonic swept wing boundary layer was selected to verify the rationality and accuracy of the method. It is shown that, the proposed local prediction formula for the key indicator factor of crossflow is reasonable, and the prediction results based on the amplification factor are in good agreement with the standard LST and wind tunnel test results.