Transition modeling is the use of a model to predict the change from laminar and turbulence flows in fluids and their respective effects on the overall solution. The complexity and lack of understanding of the underlining physics of the problems makes simulating the interaction between laminar and turbulent flow to be difficult and very case specific. Transition does have the wide range of turbulence options available for most CFD applications for the following reasons. Transition involves a wide range of scales where the energy and momentum transfer are strong influenced by inertial or non-linear effects that are unique to the simulation. Transition also occurs using different ways, (such as natural or bypass) where modelling all options are difficult. Most CFD code uses RANS where averaging eliminates linear disturbance.
Common models
The following is a list of commonly employed transition models in modern engineering applications.