Averaged equations for turbulence model are :

Boussinesq approximation is used to model Reynolds stress tensor :

It is a model with two equations on k and w :

For DDES kw-sst the model length scale is calculated as :

Model OES (Organised Eddy Simulation) is used when turbulence is not in equilibrium and enables to see Von Kármán effects. This model is based on the k epsilon model. Equations for k epsilon model are :