Correlation-Based Transition Transport Modeling for Simulating Crossflow Instabilities

A correlation-based transition model has been developed by Langtry and Menter for modern computational fluid dynamics codes, which is widely used for transition prediction in the field of turbomachinery and aircraft. Langtry’s transition model could simulate bypass, laminar separation and streamwsie Tollmien–Schlichting wave transition. Even so, this model has no ability to predict the transition due to crossflow instabilities in three dimensional boundary layer. In this paper, a new correlation-based transport equation for the transition due to crossflow instabilities has been established based on the experiment data and self-similar equations. The new transport equation is introduced to describe the crosswise displacement thickness Reynolds number growth in boundary layer. This new equation is added to Langtry’s intermittency factor equation to improve the ability of predicting transition. Finally, coupling of these transport equations and Shear Stress Transport (SST) turbulence model completes the new improved transition turbulence model. Comparisons of predictions using the new model with wind tunnel experiments of NLF (۲)-۰۴۱۵ infinite swept wing and ۶:۱ inclined prolate spheroid validate the predictive qualities of the new correlation based transport equation.

Keywords:

Boundary layer transition , Turbulence , Laminar flow , Transition model , Crossflow instabilities