Transition modelling with dynamic equations of intermittency


The transition model expresses the intermittency during laminar-turbulent transition by a dynamic equation for free-stream intermittency and one for near-wall intermittency, combined with the k-ω SST RANS turbulence model. The free-stream factor describes the intermittent behaviour of the turbulent eddies, coming from the free stream, impacting onto the boudary layer. The near-wall factor represents the fraction of time during which velocity fluctuations caused by break-up inside the boundary layer, have a turbulent character. Transition onset and growth rate are derived from correlations for attached state and separated state transition in steady flow. The performance of the model is verified on two turbine blade cascades, with one test-case with transition in steady flow and attached state, one test-case with transition by wake impact in attached boundary layer state and two test-cases with transition by wake impact in separated boundary layer state.


  • KUBACKI S., LODEFIER K., ZARZYCKI R., ELSNER W., DICK E.: Further development of a dynamic intermittency model for wake-induced transition on turbine blades. Flow, Turbulence and Combustion, 83 (2009), 539-568.
  • PIOTROWSKI W., LODEFIER K., KUBACKI S., ELSNER W., DICK E.: Comparison of two unsteady intermittency models for bypass transition prediction on a turbine blade profile. Flow, Turbulence and Combustion, 81 (2008), 369-394.
  • LODEFIER K., DICK E.: Modelling of unsteady transition in low-pressure turbine blade flows with two dynamic intermittency equations. Flow, Turbulence and Combustion, 76 (2006), 103-132.
  • LODEFIER K., MERCI B., DE LANGHE C., DICK E.: Intermittency based RANS bypass transition modelling. Progress in Computational Fluid Dynamics, 6 (2006), 68-78.
  • LODEFIER K., MERCI B., DE LANGHE C., DICK E.: Transition modelling with the k-ω turbulence model and an intermittency transport equation. J. of Thermal Science, 13 (2004), 220-225.