Some of the main deficiencies of the Reynolds stress models for the simulation of boundary layers are an inheritance from the underlying -equation. Particularly the accurate prediction of flow separation is problematic when the -equation is used. Furthermore, low-Reynolds number formulations for the -equation are usually complex and difficult to integrate, a deficiency that is exaggerated in combination with a Reynolds stress model formulation. In order to avoid these issues, a Reynolds stress model has been implemented that uses the -equation instead of the -equation as the scale-determining equation.

There are two types of SMC- model in CFX:

As the freestream sensitivity of the standard model does carry over to the Reynolds stress model, the BSL Reynolds stress model was developed, which is based on the -equation used in the BSL model, and is preferred over the Omega Reynolds stress model. This is the formulation recommended when using the -Reynolds stress model.

All variants of the -Reynolds stress model are combined with automatic wall treatment, which allows a flexible grid resolution near the wall. For details, see: