Development of a computational fluid dynamics compatible mathematical model for boundary layer transitional flows in low-disturbance environment

Because of the great influence of transition phenomena in aerodynamic property calculations, boundary layer transition has always been a hot research topic in the past few decades. Meanwhile, the prediction methods for boundary layer transition need to be established, researched and enhanced. In order to build a computational fluid dynamics (CFD) compatible transition model, the authors propose a two-equation transport transition model in this paper considering analysis results through linear stability theory (LST). This new transition model consists of one transport equation for laminar fluctuation kinetic energy and another for intermittency factor. Without boundary layer integration and other nonlocal operations, all the variables in this new transition model can be calculated locally so that present model is compatible with CFD parallel computation. Laminar separation bubble induced transition, Tollmien–Schlichting (T–S) instabilities and stationary crossflow instabilities (CF) dominated transition are modeled in the transport equation. The validation tests have been conducted on the classical Schubauer & Klebanoff flat plate, natural laminar airfoil NLF(1)-0416, NLF(2)-0415 infinite swept wing, classical sickle swept wing and 6:1 inclined prolate spheroid using this fully-local transition model. Since all the test cases are in accord with experimental data, the present transition model could be widely applied to aeronautical flows in low-disturbance environment.