Recent improvement of a correlation-based transition turbulence model for simulating three-dimensional boundary layers

Abstract

In the present study, an improved laminar-turbulence transition model ᵞ-Reθt-CF+ has been developed for simulating three-dimensional flow transition including the effect of interaction between the Tollmien-Schlichting and cross flow instabilities. To predict the acceleration of the transition process due to the interaction between the two instabilities, a new trigger function, Fonset1_infer, was introduced into the previously proposed ᵞ-Reθt-CF model. In the formulation of the present ᵞ-Reθt-CF+ model, the main modification was made in the trigger function. As a result, the present model primarily works on local flow variables, and thus can be effectively implemented in the CFD solvers based on unstructured meshes by inheriting the advantages of the baseline ᵞ-Reθt transition model. Validations of the present ᵞ-Reθt-CF+ transition model were made for an infinite NLF(2)-0415 swept wing configuration, an inclined 6:1 prolate spheroid, and a finite ONERA M6 swept wing. The results of the present transition model were compared with those of the ᵞ-Reθt model, ᵞ-Reθt-CF model, and the experiment. It was found that the present y-Re9t-CF+ model is well established, and is useful for predicting the flows involving three-dimensional laminarturbulence transition more accurately than the ᵞ-Reθt model and the ᵞ-Reθt-CF model for general engineering flow problems by including the effect of the interaction between the Tollmien-Schlichting and cross flow instabilities.