Numerical Simulation of Bypass Transition by the Approach of Intermittency Transport Equation

Abstract

This paper deals with the development of a numerical approach to predict freestream turbulence-induced (FST-induced) boundary layer bypass transition using an intermittency transport equation. An intermittency based transition model, which is critical for invoking transition onset according to Abu-Ghannam and Shaw correlation, is implemented into the proven Reynolds-Averaged N-S (RANS) solver. The intermittent behavior of the transitional flow is incorporated into the computation by modifying the eddy viscosity µt , obtained from a turbulence model. Wilcox low Reynolds k –ω turbulence model is employed to calculate the eddy viscosity and others turbulent quantities. For validation, the present transition model is applied to the benchmark experiments of flat plate test cases of ERCOFTAC series and to predictions of a modern Low Pressure (LP) turbine flow. It follows from the detail comparisons of the calculated results with the relevant experimental data and other researchers' simulations that the present model is capable to make a reasonable prediction of FST-induced bypass transition.

Keywords

• boundary layer
• bypass transition
• numerical prediction
• intermittency factor