Prediction of Laminar Separation bubbles with Algebraic turbulence models

摘要

the most frequently used turbulence model for the laminar separation bubble may be algebraic models. Algebraic models assume local equilibrium, and empirically describe the turbulence velocity and length scales As algebraic functions of the local mean flow variables. The Boussinesq eddy-viscosity is assumed to be related Only to the mean motion. In the present study, two popular algebraic models. Cebeci-Smith model and Baldwin-Lomax model, are employed with combination of transition functions to simulate the process of Laminar-turbulent transition. Considering non-equilibrium effects of laminar-turbulent transitional flow, an Ordinary differential equation is developed for the transition function instead of the conventional intermittency Factor. Numerical results are compared with experimental measurement.